Kehamilan Lewat Waktu

Kehamilan Lewat Waktu

Masalah yang dihadapi pada kehamilan lewat waktu Kehamilan lewat waktu adalah kehamilan yang melampaui usia 294 hari (42 minggu) dengan segala kemungkinan komplikasinya. komplikasinya. Nama lain kehamilan lewat waktu adalah kehamilan serotinus, prolonged pregnancy, atau post-term pregnancy. Kehamilan normal ditandai dengan gerak janin 7-10/20 menit, denyut jantung janin 120-140/  menit, usia kehamilan 37-42 minggu (rata-rata 37-40 minggu), dan berat janin 2.500-4.000 gram. Penyebab terjadinya kehamilan lewat waktu adalah adanya ketidakpastian mengetahui tanggal haid terakhir, terdapat kelainan kongenital anensefalus, atau terdapat hipoplasia kelenjar adrenal. Komplikasi Kehamilan Lewat Waktu Komplikasi kehamilan lewat waktu terjadi baik pada ibu maupun janin. Komplikasi pada ibu meliputi timbulnya rasa takut akibat terlambat melahirkan mel ahirkan atau rasa takut menjalani operasi yang mengakibatkan mengakibatkan trias komplikasi ibu. Komplikasi pada janin meliputi hal-hal berikut ini.- Oligohidramnion. Air ketuban normal pada kehamilan 34-37 minggu adalah 1.000 cc, aterm 800 cc, dan lebih dari 42 minggu 400 cc. Akibat oligohidramnion adalah amnion menjadi kental karena mekonium (diaspirasi oleh janin), asfiksia intrauterin (gawat janin), pada in partu (aspirasi air ketuban, nilai Apgar rendah, sindrom gawat paru, bronkus paru tersumbat sehingga menimbulkan atelektasis). - Warna mekonium. Mekonium keluar karena refleks vagus terhadap usus. Peristaltik usus dan terbukanya sfingter ini membuat mekonium keluar. Aspirasi air ketuban yang disertai mekonium dapat menimbulkan gangguan pernapasan bayi/ janin, gangguan sirkulasi bayi setelah lahir, dan hipoksia intrauterin sampai kematian janin. - Makrosomia. Dengan plasenta yang masih baik, terjadi tumbuh-kembang janin dengan berat 4.500 gram yang disebut makrosomia. Akibatnya terhadap persalinan adalah perlu dilakukannya dilakukannya tindakan operatif seksio sesaria, dapat terjadi trauma t rauma persalinan karena operasi vaginal, distosia bahu yang menimbulkan kematian bayi, atau trauma jalan lahir ibu. - Dismaturitas bayi. Pada usia kehamilan 37 minggu, luas plasenta 11 m2. Selanjutnya, terjadi penurunan fungsi sehingga plasenta tidak berkembang atau terjadi kaisifikasi dan aterosklerosis pembuluh darah. Penurunan kemampuan nutrisi plasenta menimbulkan perubahan metabolisme menuju anaerob sehingga terjadi badan keton dan asidosis. Terjadi dismaturitas dengan gejala Clifford yang ditandai dengan: a. kulit: subkutan berkurang dan diwarnai mekonium; b. otot makin lemah; c. kuku tampak panjang; d. tampak keriput; e. tali pusat lembek, l embek, mudah tertekan dan disertai oligo-hidramnion. Pemeriksaan USG bertujuan untuk mengetahui usia kehamilan, kondisi oligohidramnion, klasifikasi plasenta, kelainan kongenital, pergerakan pergerakan janin (aktivitasnya 7-10/ 30 menit), dan pernapasan janin. Masalah yang dihadapi pada kehamilan lewat waktu adalah risiko terhadap janin, waktu yang tepat untuk melakukan persalinan, menentukan persalinan per vagina versus per abdominal. Risiko kehamilan sulit dipastikan sehingga dapat menjurus risiko kematian janin intrauterin

dan risiko makrosomia. Pada kehamilan lewat waktu, persalinan perlu dipercepat bila terj adi preeklampsia/ eklampsia, ibu dengan hipertensi, ibu dengan diabetes melitus, dan gangguan tumbuh-kembang janin intrauterin. Pada kehamilan lewat waktu juga dihadapi masalah kematangan serviks. Teknik Pertolongan Persalinan Teknik pertolongan persalinan pada kehamilan lewat waktu adalah dengan induksi oksitosin atau seksio sesaria. Masalah yang dihadapi pada kehamilan lewat waktu Kehamilan lewat waktu adalah kehamilan yang melampaui usia 294 hari (42 minggu) dengan segala kemungkinan komplikasinya. Nama lain kehamilan lewat waktu adalah kehamilan serotinus, prolonged pregnancy, atau post-term pregnancy. Kehamilan normal ditandai dengan gerak janin 7-10/20 menit, denyut jantung janin 120-140/  menit, usia kehamilan 37-42 minggu (rata-rata 37-40 minggu), dan berat janin 2.500-4.000 gram. Penyebab terjadinya kehamilan lewat waktu adalah adanya ketidakpastian mengetahui tanggal haid terakhir, terdapat kelainan kongenital anensefalus, atau terdapat hipoplasia kelenjar adrenal. Komplikasi Kehamilan Lewat Waktu Komplikasi kehamilan lewat waktu terjadi baik pada ibu maupun janin. Komplikasi pada ibu meliputi timbulnya rasa takut akibat terlambat melahirkan atau rasa takut menjalani operasi yang mengakibatkan trias komplikasi ibu. Komplikasi pada janin meliputi hal-hal berikut ini.- Oligohidramnion. Air ketuban normal pada kehamilan 34-37 minggu adalah 1.000 cc, aterm 800 cc, dan lebih dari 42 minggu 400 cc. Akibat oligohidramnion adalah amnion menjadi kental karena mekonium (diaspirasi oleh janin), asfiksia intrauterin (gawat janin), pada in partu (aspirasi air ketuban, nilai Apgar rendah, sindrom gawat paru, bronkus paru tersumbat sehingga menimbulkan atelektasis). - Warna mekonium. Mekonium keluar karena refleks vagus terhadap usus. Peristaltik usus dan terbukanya sfingter ini membuat mekonium keluar. Aspirasi air ketuban yang disertai mekonium dapat menimbulkan gangguan pernapasan bayi/ janin, gangguan sirkulasi bayi setelah lahir, dan hipoksia intrauterin sampai kematian janin. - Makrosomia. Dengan plasenta yang masih baik, terjadi tumbuh-kembang janin dengan berat 4.500 gram yang disebut makrosomia. Akibatnya terhadap persalinan adalah perlu dilakukannya tindakan operatif seksio sesaria, dapat terjadi trauma persalinan karena operasi vaginal, distosia bahu yang menimbulkan kematian bayi, atau trauma jalan lahir ibu. - Dismaturitas bayi. Pada usia kehamilan 37 minggu, luas plasenta 11 m2. Selanjutnya, terjadi penurunan fungsi sehingga plasenta tidak berkembang atau terjadi kaisifikasi dan aterosklerosis pembuluh darah. Penurunan kemampuan nutrisi plasenta menimbulkan perubahan metabolisme menuju anaerob sehingga terjadi badan keton dan asidosis. Terjadi dismaturitas dengan gejala Clifford yang ditandai dengan: a. kulit: subkutan berkurang dan diwarnai mekonium; b. otot makin lemah; c. kuku tampak panjang; d. tampak keriput; e. tali pusat lembek, mudah tertekan dan disertai oligo-hidramnion.

Pemeriksaan USG bertujuan untuk mengetahui usia kehamilan, kondisi oligohidramnion, klasifikasi plasenta, kelainan kongenital, pergerakan janin (aktivitasnya 7-10/ 30 menit), dan pernapasan janin. Masalah yang dihadapi pada kehamilan lewat waktu adalah risiko terhadap janin, waktu yang tepat untuk melakukan persalinan, menentukan persalinan per vagina versus per abdominal. Risiko kehamilan sulit dipastikan sehingga dapat menjurus risiko kematian janin intrauterin dan risiko makrosomia. Pada kehamilan lewat waktu, persalinan perlu dipercepat bila terjadi preeklampsia/ eklampsia, ibu dengan hipertensi, ibu dengan diabetes melitus, dan gangguan tumbuh-kembang janin intrauterin. Pada kehamilan lewat waktu juga dihadapi masalah kematangan serviks. Teknik Pertolongan Persalinan Teknik pertolongan persalinan pada kehamilan lewat waktu adalah dengan induksi oksitosin atau seksio sesaria. BAB I PENDAHULUAN

A. Latar Belakang Kehamilan lewat waktu adalah kehamilan yang melampui usia 284 hari (42 minggu) dengan segala kemungkinan komplikasinya. Nama lain kehamilan lewat waktu adalah kehamilan serotinus, prolonged pregenec atau post-term pregenancy. Kehamilan normal ditandai dengan gerak janin 7-10/20 menit, denyut jantung janin 120-140/ menit, usia kehamilan 37-42 minggu (rata-rata 37-40 minggu) dengan berat janin 2.500 – 4.000 gram. Penyebab terjadinya kehamilan lewat Waktu adalah adanya ketidakpastian mengetahui tanggal haid terakhir, terdapat kelainan kongenital anensefalus, atau terdapat hipoplasia kelenjar adrenal. B. Tujuan Tujuan Umum Agar penulis mendapatkan pengetahuan dan pengalaman yagn nyata dari teori yang diperoleh sehingga penulis mampu melakukan dan menerapkan asuhan kebidanan pada ibu hamil KEHAMILAN LEWAT WAKTU (POST DATE) A. Pengertian Kehamilan lewat waktu adalah kehamilan yang melewati 294 hari atau 42 minggu lengkap. (Kapita Selekta Jilid 1 : 274). Kehamilan lewat waktu adalah kehamilan yang melebihi 42 minggu belum terjadi persalinan. (Manuaba, 222). Kehamilan Post Matur adalah kehamilan yang berlansung lebih lama dari 42 minggu dihitung berdasarkan rumus Naogle dengan siklus haid rata-rata 28 hari. (Rustam Mochtar : 221). B. Etiologi

Menjelang persalinan terjadi penurunan progesteron, peningkatan okstitosin tubuh dan reseptor terhadap pada kehamilan lewat waktu terjadi sebaliknya, otot rahim tidak sensitiv terhadap rangsangan karena ketegangan psikologis atau kelainan pada rahim. C. Permasalahan Kehamilan Lewat Waktu Permasalahan kehamilan lewat waktu adalah plasenta tidak sanggup memberikan nutrisi dan pertukaran O2 sehingga janin mempunyai resiko sampai kematian dalam rahim. Makin menurunnya sirkolasi darah menuju sirkulasi plasenta dapa mengakibatkan : - Pertumbuhan  janin main lambat. - Terjadi perubahan dengan metabolisme janin. - Air ketuban berkurang dan makin kental. - Sebagian janin bertambah berat, sehingga memerlukan tindakan operasi persalinan. - Berkurangnya nutrisi O2 kejanin mengakibatkan asfiksia dan setiap saat dapt meninggal dalam rahim. - Dalam persalinan janin lebih muda mengalami asfiksia kematian  janin pada kehamilan lewat waktu dapat terjadi sekitar 25% sampai 35% dalam rahim dan makin meningkat pertolongan persalinan dengan tindakan.

D. Tanda-Tanda Bayi Post Matur - Biasnaya lebih berat dari bayi matur. - Tulang dan sutura kepala lebih keras dari bayi matur. - Rambut lanugo hilang atau sangat kurang. - Verniks kaseosa dibadan sangat kurang. - Kuku-kuku sangat panjang. - Rambut kepala agak tebal. - Kulit agak pucat dengan diskuaminasi epitel. Atau dapt dibagi dalam 3 stadium : 1. Stadium 1 Kulit menunjukkan kehilangan verniks kaseosa dan maserasi berupa kulit kering rapuh dan mudah mengelupas. 2. Stadium 2 Gejala diatas disertai perwanaan meconium (kehijauan) pada kulit. 3. Stadium 3 Terdapat perwarnaan kekuningan pada kulit atau tali pusat. E. Pengaruh Terhadap ibu dan Janin Terhadap ibu Persalinan post matur dapat menyebabkan distosia karena : a. b. c. d.

Aksi uterus tidak terkoordinir. Janin besar. Moulding kepala besar Maka akan sering dijumpai partus lama, kesalahan letak, inersia uteri, distosia bahu dan perdarahan post partum.

e. Terhadap janin f. Jumlah kematian janin/ bayi pada kehamilan 42 minggu 3x lebih bear dari kehamilan 40 minggu, karena post maturitas pada janin bervariasi, berat badan janin bertambah besar, tetap dan ada yang berkurang, sesudah kehamilan 42 minggu ada pula yang bisa terjadi kematian janin dalam kandungan. Penentu Keadaan Janin (Penilaian) Sebagai berikut : a.Tes tanpa tekanan (Non Stress Test). Bila memperoleh hasil non reaktif maka dilanjutkan dengan tes tekanan oksitosin. Bila didapat hasil reaktif maka nilai spesifetas 98,8% menunjukkan kemungkinan besar janin baik, bila ditemukan hasil tes tekanan yang positif  meskipun sensitifitas relatif rendah tetapi telah dibuktikan berhubungan dengan negatif  keadaan prematur. b. Gerakan janin Secara subyektif normal rata-rata 7 x 20 menit. Gerakan janin dapt pula ditentukan dengan pemeriksaan USE. c. Amnioskopi Bila ditemukan air ketuban yang banyak dan jernih mungkin keadaan janin masih baik, sebaliknya air ketuban sedikit dan mengandung meconium akan mengalami resiko 30% asfiksia. Diagnosis - Bila tanggal hari pertama haid terakhir dicatat dan ketahui wanita hamil diangosis tidak  sukar. - Bila wanita tidak tahu, lupa atau tidak ingat, atau sejak melahirkan yang lalu tidak  dapt diikuti tinggi dan naiknya fundus uteri, mulai gerakan janin dan besarnya janin dapat membantu diagnosis. - Pemeriksaan BB diikuti, kapan menjadi kurang, begitu pula lingkaran perut dan jumlah air ketuban apakah berkurang. - Pemeriksaan rontgenologik dapt dijumpai pusat penalangan pada bagian distal femur, bagian proksimal tibia, tulang kubola, diameter biparietal 9.8 cm atau lebih. - USG : UKUrang diamter biparetal, gerakan janin dan jumlah air ketuban. - Pemeriksaan sitologik air ketuban, air ketuban diambil dengan amnio sintesis baik tirasvaginal maupun trasabdominal, air ketuban akan bercampur lemak dan sel-sel kulit yang dilepas janin setelah kehamilan mencapai lebih dari 36 minggu. Air ketuban yang diperoleh dipulas dengan sulfat bironil. Maka sel-sel yang mengandung lemak akan berwarna  jingga alba. a. Melebihi 10% : Kehamilan diatas 36 minggu. b. Melebihi 50% : Kehamilans diatas 39 minggu. - Amnioskopi : Melihat derajat air ketuban, menurut warnanya karena diketahui mekonium. - Kardiografi : Mengawasi dan membaca denyut jantung janin, karena insufisensi plasenta. - Uji Oksitosin (Stress test) : Yaitu dengan infus tetes oksitosin dan diawasi raksi janin terhadap kontraksi uterus, jika ternyata reaksi janin kurang baik, ini akan membahayakan janin. - Pemeriksaan kadar estriol dan urine. - Pemeriksaan Ph darah kepala janin. - Pemeriskaan Sitologi Vagina. b. Melebihi 50% : Kehamilans diatas 39 minggu. - Amnioskopi : Melihat derajat air ketuban, menurut warnanya karena diketahui mekonium. - Kardiografi : Mengawasi dan membaca denyut jantung janin, karena insufisensi plasenta. - Uji Oksitosin (Stress test) : Yaitu dengan infus tetes oksitosin dan diawasi raksi janin terhadap kontraksi uterus, jika ternyata reaksi janin kurang baik, ini akan membahayakan janin. - Pemeriksaan kadar estriol dan urine. - Pemeriksaan Ph darah kepala janin. - Pemeriskaan Sitologi Vagina.

- Pukul 18.00 : Hanya suntikan pitoltrin 0.2 cc Sekalipun metode stein sudah ditinggalkan, tetapi untuk pengethauan bidan masih perlu diketahui, selama metode stein, kehamilan lewat waktu mendapatkan : a.1,2 gr bisulfas kinine. b.1,4 gr pitotrin injeksi Persalinan anjuran dengan metode ini diluar rumah sakit berbahasa karena dapat tejradi : -

Kontraksi rahim yang kuat sehingga dapat mengancam Ketuban pecah saat pembukaan kecil. Reptur uteri membakat. Gawat janin dalam rahim. 2. Persainan anjuran dengan infus pitoltrin (Sitosinon) Persalinan anjuran dengan infus oksitosin, pitoltrin atau sitosinon 5 unit dalam 500 cc glukosa 5% banyak dipergunakan. Teknik induksi dengan infus glukosa lebih sederhana, dan mulai dengan 8 tetes dengan makismal 40 tetes/ menit kenaikan tetesan setiap 15 menit sebanyak 4 sampai 8 tetes sampai kontraksi optimal tercapai. Maka tetesan tersebut dipertahankan sampai terjadi persalinan apabila terjadi kegagalan, ulangi persalinan anjuran dengan selang waktu 24 jam sampai 48 jam. Memecahkan ketuban Memecahkan ketuban merupakan salah satu metode untuk  mempercepat persalinan. Setleah ketuban pecah ditunggu sekitar 4 sampai 6 jam dengan harapan otot rahim akan berlangsung apabila belum berlangsung kontraksi otot rahim dapat diikuti induksi persalinan dengan infus glukosa yang mengandung 5 unit oksitosin. 4. Persalinan anjuran dengan menggunakan prostaglandin. Telah diketahui bahwa kontraksi otot rahim terutama dirangsang oleh protaglanin, pemakaian prostaglandin sebagai induksi persalinan dapat dalam bentuk infus intravena (nasages) dan pervaginam (Prostaglandin Vagina Suppositoria). • Penyulit persalinan anjuran (induksi persalinan) Dalam melakukan persalinan anjuran dapat terjadi penyulit yang membahagiakan ibu maupun janin, sebagai berikut : a. Penyulit ibu (Maternal) - Kontrkasi otot rahim yang berlebihan, sehingga dapat menimbulkan ruptor uteri membakat. - Kontraksi otot rahim yang berlebihan mengganggu sirkulasi darah sehingga menimbulkan asfiksi janin. - Kelebihan cairan yang diberikan dapat menimbulkan : 1. Edema paru : Sesak nafas dan sianosis 2. Tekanan meningkat, terjadi pendarahan otak 3. Memecahkan ketuban, dapat menimbulkan infeksi b. Penyulit untuk   janin - Kontraksi otot rahim menimbulkan asfiksia janin dalam rahim. - Ketuban pecah dalam pembukaan kecil 1. Persalinan berlangsung lebih dari 6 janin menyebabkan bahaya infkesi. 2. Derasnya air ketuban dapat menimbulkan prolapsis tali pusat, prolapsis tangan atau kaki menimbulkan penyulit teknik persalinan - Persalinan yang berlangsung lama 1. Menimbulkan kelelahan ibu, dehidrasi, edema bagian bawah. 2. Bahaya infeksi Persalinan anjuran meurpakan percobaan untuk membuktikan ketidakseimbangan diantara janin dan jalan lahir.

Postterm Pregnancy [1]

Postterm pregnancy is defined as a pregnancy that extends to 42 0/7 weeks and beyond . The [1, 2] reported frequency of postterm pregnancy is approximately 3-12% . However, the actual biologic variation is likely less since the most frequent cause of a postterm pregnancy [3, 4, 5, 6] diagnosis is inaccurate dating. Risk factors for actual postterm pregnancy include [7, 8, 9, 2, 1] primiparity, prior postterm pregnancy, male gender of the fetus, and genetic factors. Laursen et al studied monozygotic and dizygotic twins and their subsequent development of  prolonged pregnancies. They found that maternal but not paternal genetic factors influenced the rate of postterm pregnancies and accounted for the etiology in as many as 30% of these [10] pregnancies. A more recently described risk factor is obesity, which appears to increase the [11, 12, 13] risk of pregnancies progressing beyond 41 or 42 weeks of gestation . Although the last menstrual period (LMP) has been traditionally used to calculate the estimated due date (EDD), many inaccuracies exist using this method in women who have irregular cycles, have been on recent hormonal birth control, or who have first trimester bleeding. In particular, women are more likely to be oligo-ovulatory than polyovulatory, so [4] cycles longer than 28 days are not uncommonly seen. If such a cycle is 35 days instead of  28 days, a second trimester ultrasound will not be powerful enough to redate the pregnancy. Thus, not only the LMP date, but the regularity and length of cycles must be taken into account when estimating gestational age. Ultrasonographic dating early in pregnancy can improve the reliability of the EDD; however, it is necessary to understand the margin of error reported at various times during each trimester. A calculated gestational age by composite biometry from a sonogram must be considered an estimate and must take into account the range of possibilities. Estimation range varies. For example, crown-rump length (CRL) is 3-5 days, ultrasonography performed at 12-20 weeks of gestation is 7-10 days, at 20-30 weeks is 2 weeks, and after 30 weeks is 3 weeks. Thus, a pregnancy that is 35 weeks by a 31-week ultrasound could actually be anywhere from 32 weeks to 38 weeks (35 wk +/-3 wk). If the calculated ultrasonographic

gestational age varies from the LMP more than the respective range of error, it is used instead to establish the final EDD. The importance of determining by what method a pregnancy is dated cannot be overemphasized because this may have significant consequences if the physician delivers a so-called term pregnancy that is not or observes a so-called term pregnancy that is very postterm. When determining a management plan for an impending postterm pregnancy (>40 wk of  gestation but < 42 wk), the 3 options are (1) elective induction of labor, (2) expectant management of the pregnancy, or (3) antenatal testing. Each of these 3 options may be used at any particular time during this 2-week period. Note that if the pregnancy is at risk for an adverse outcome from an underlying condition, either maternal or fetal, inducing labor may proceed without documented lung maturity. Also, an elective induction of labor may proceed at or after 39 weeks of gestation in the absence of  documented lung maturity provided that 36 weeks have elapsed since documentation of a positive human chorionic gonadotropin (+hCG) test finding, 20 weeks of fetal heart tones have been established by a fetoscope or 30 weeks by a Doppler examination, or 39 weeks' gestation have been established by a CRL or by an ultrasound performed before 20 weeks of  gestation consistent with dates by the patient's LMP. Perinatal outcomes in postterm pregnancies [14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26]

Recent studies have shown that the risks to the fetus and to [23, 27, 28, 29, 30, 31, 32, 33] the mother of continuing the pregnancy beyond the estimated date of  delivery is greater than originally appreciated. Risks have traditionally been underestimated for 2 reasons. First, earlier studies were published before the routine use of obstetric ultrasonography and, as a result, likely included many pregnancies that were not truly postterm. As noted above, such a misclassification bias would artificially lower the complication rates of pregnancies designated postterm and increase the complication rates in those designated term, resulting in a diminution in the difference between term and postterm pregnancies. The second issue relates to the definition of stillbirth rates. Traditionally, stillbirth rates were calculated using all pregnancies delivered at a given gestational age as the denominator. However, once a fetus is delivered, it is no longer at risk of intrauterine fetal demise, and use of this denominator has traditionally underestimated the risk of stillbirth. The appropriate denominator is not all deliveries at a given gestational age, but ongoing (undelivered) [18, 19, 33] pregnancies. In one retrospective study of more than 170,000 singleton births, for example, Hilder et al demonstrated that the stillbirth rate increased 6-fold (from 0.35-2.12 per 1,000 pregnancies) when the denominator was changed from all deliveries to ongoing [16] (undelivered) pregnancies. Fetal and neonatal risks Antepartum stillbirths account for more perinatal deaths than either complications of  [17] prematurity or sudden infant death syndrome. Perinatal mortality (defined as stillbirths plus early neonatal deaths) at 42 weeks of gestation is twice that at 40 weeks (4-7 vs 2-3 per 1,000 deliveries, respectively) and increases 4-fold at 43 weeks and 5- to 7-fold at 44

[15, 16, 17]

weeks. These data also demonstrate that, when calculated per 1000 ongoing [16] pregnancies, fetal and neonatal mortality rates increase sharply after 40 weeks. Cotzias et al calculated the risk of stillbirth in ongoing pregnancies for each gestational age [17] from 35-43 weeks. The risk of stillbirth was 1 in 926 ongoing pregnancies at 40 weeks’ gestation, 1 in 826 at 41 weeks, 1 in 769 at 42 weeks, and 1 in 633 at 43 weeks. Uteroplacental insufficiency, asphyxia (with and without meconium), intrauterine infection, and anencephaly all contribute to excess perinatal deaths, although postterm anencephaly is [34] essentially nonexistent with modern obstetrical care . A number of key morbidities are greater in infants born t o postterm pregnancies as well as pregnancies that progress to and beyond 41 0/7 weeks gestation including meconium and meconium aspiration, neonatal academia, low Apgar scores, macrosomia, and, in turn, birth injury. For example, since postterm infants are larger than term infants, with a higher incidence of fetal macrosomia (defined as estimated fetal weight ≥ 4,500 g)[35] , they are, in [36, 37] turn, at greater risk for other complications. Such complications associated with fetal macrosomia include prolonged labor, cephalopelvic disproportion, and shoulder dystocia with resultant risks of orthopedic or neurologic injury. Approximately 20% of postterm fetuses have fetal dysmaturity (postmaturity) syndrome, which describes infants with characteristics of chronic intrauterine growth restriction from [38] uteroplacental insufficiency. These pregnancies are at increased risk of umbilical cord compression from oligohydramnios, nonreassuring fetal antepartum or intrapartum assessment, intrauterine passage of meconium, and short-term neonatal complications (such as hypoglycemia, seizures, and respiratory insufficiency). Meconium aspiration syndrome refers to respiratory compromise with tachypnea, cyanosis, and reduced pulmonary compliance in newborns exposed to meconium in utero and is seen in [39] higher rates in postterm neonates. Indeed, the 4-fold decrease in the incidence of the meconium aspiration syndrome in the United States from 1990-1998 has been attributed [21] primarily to a reduction in the postterm delivery rate with very little contribution from conventional interventions designed to protect the lungs from the chemical pneumonitis [40, 41] caused by chronic meconium exposure, such as amnioinfusio n or routine [42] nasopharyngeal suctioning of meconium-stained neonates. [43]

Postterm pregnancy is also an independent risk factor for neonatal encephalopath y [16, 17] death in the first year of life.

and for

While much of the work above has been conducted in postterm pregnancies. Some of t he fetal risks such as presence of meconium, increased risk of neonatal academia, and even stillbirth have been described as being greater at 41 weeks of gestation and even at 40 weeks [22, 23] of gestation as compared with 39 weeks’ gestation. For example, in one study, the rates of meconium and neonatal academia both increased throughout term pregnancies beyond 38 weeks of gestation. In addition to stillbirth being increased prior to 42 weeks of gestation, one study found that the risk of neonatal mortality also increases beyond 41 weeks of  [44] gestation. Thus, 42 weeks does not represent a threshold below which risk is uniformly distributed. Indeed, neonatal morbidity (including meconium aspiration syndrome, birth injury, and neonatal acidemia) appears to be the lowest at around 38 weeks and increase in a [45] continuous fashion thereafter.

While preterm delivery is a well-established risk factor for cerebral palsy, a recent study suggested that delivery at 42 weeks or later is also associated with increased risk (RR 1.4, [46] 95% CI, 1.2-1.6 when compared with delivery at 40 weeks’ gestation). Maternal risks and mode of delivery The maternal risks of postterm pregnancy are often underappreciated. These include an rd increase in labor dystocia (9-12% vs 2-7% at term), an increase in severe perineal injury (3 th and 4 degree perineal lacerations) related to macrosomia (3.3% vs 2.6% at term) and operative vaginal delivery, and a doubling in the rate of cesarean delivery (14% vs 7% at [18, 27, 28, 29] term). The latter is associated with higher risks of complications such as [28, 47] endometritis, hemorrhage, and thromboembolic disease. In addition to the medical risks, the emotional impact (anxiety and frustration) of carrying a pregnancy 1-2 weeks beyond the estimated due date should not be underestimated. In a randomized, controlled trial of women at 41 weeks of gestation, women who were induced would desire the same management 74% of the time, whereas women with serial antenatal [48] monitoring only desired the same management 38% of the time. Similar to neonatal outcomes, maternal morbidity also increases in term pregnancies prior to 42 weeks of gestation. Such complications as chorioamnionitis, severe perineal lacerations, cesarean delivery rates, postpartum hemorrhage, and endomyometritis all increase [23, 30, 31, 32, 21] progressively after 39 weeks of gestation. Timing of Delivery The first decision that must be made when managing an impending postterm pregnancy is whether to deliver. In certain cases (eg, nonreassuring surveillance, oligohydramnios, growth restriction, certain maternal diseases), the decision is straightforward. In these high-risk  situations, the time at which the risks of remaining pregnant begin to outweigh the risks of  delivery may come at an earlier gestational age (eg, 39 weeks of gestation). However, frequently several options can be considered when determining a course of action in the lowrisk pregnancy. The certainty of gestational age, cervical examination findings, estimated fetal weight, patient preference, and past obstetric history must all be considered when mapping a course of action. The main argument against a policy of routine induction of labor at 41 0/7 to 41 6/7 weeks has been that induction increases the rate of cesarean delivery without decreasing maternal and/or neonatal morbidity. Some of the studies that failed to show a reduction in fetal/neonatal morbidity were diluted by poorly dated pregnancies that were not necessarily postterm. In addition, the potential for increasing the risk for cesarean delivery with a failed induction is far less likely in the era of safe and effective cervical ripening agents. To date, more than 10 studies have been published of elective induction of labor, many of  [49, 34, 50, 51, 52, 53] them at 41 weeks of gestation. The preponderance of the evidence from these studies, including meta-analyses, find that not only is rate of cesarean delivery not increased in women who were randomized to routine induction of labor, but also more cesarean deliveries were performed in the noninduction groups, and the most frequent indication was fetal distress. Even with multiple studies, very few neonatal differences have been

demonstrated. However, the reduction in meconium is statistically significant and the rate of  neonatal mortality is lower. In summary, routine induction at 41 weeks of gestation does not increase the cesarean delivery rate and may decrease it without negatively affecting perinatal morbidity or mortality. In fact, both the woman and the neonate benefit from a policy of routine induction of labor in well-dated, low-risk pregnancies at 41 weeks' gestation. Because it is associated with a lower rate of adverse outcomes, including shoulder dystocia and meconium aspiration [54] syndrome, this policy may also prove to be more cost-effective. A policy of routine induction at 40 weeks' has few benefits, and there are multiple reasons not to allow a pregnancy to progress beyond 42 weeks. Prior to 41 weeks of gestation, the evidence becomes more scant with only 3 small, non-US, randomized, controlled trials comparing elective induction of labor to expectant management [52] of pregnancy. However, elective induction of labor is increasingly being used as a [55, 56] management strategy. While this management may be reasonable in a practice that allows 48 hours or more for the management of the latent phase and the first stage of labor overall, in a setting where induction of labor is called a failure after 18-24 hours, it will likely further increase the cesarean delivery rate. Cervical Ripening and Intrapartum Management Once the decision to deliver a patient has been made, the management of the labor induction depends on the clinical setting, and a brief review of cervical ripening agents and potential complications of induction of labor is appropriate. A comprehensive review of all available methods for cervical ripening, indications, contraindications, and dosing is beyond the scope of this article. As many as 80% of patients who reach 42 weeks' gestation have an unfavorable cervical examination (ie, Bishop Score < 7). Many options are available for cervical ripening. The different preparations, indications, contraindications, and multiple dosing regimes of each require practitioners to familiarize themselves with several of the preparations. Prostaglandin E2 gel and suppositories for vaginal application were used extensively until the late 1990s when many pharmacies stopped manufacturing them because of the advent of  commercially available and less labor-intensive preparations. Currently available chemical preparations include prostaglandin E1 tablets for oral or vaginal use (misoprostol), prostaglandin E2 gel for intracervical application (dinoprostone cervical [Prepidil]), and a prostaglandin E2 vaginal insert (dinoprostone [Cervidil]). Cervidil contains 10 mg of  dinoprostone and has a lower constant release of medication than Prepidil. In addition, this vaginal insert device allows for easier removal in the event of uterine hyperstimulation. Many studies have compared the efficacy and risks of various prostaglandin cervical ripening agents. Rozenburg et al performed a randomized trial comparing intravaginal misoprostol and dinoprostone vaginal insert in pregnancies at high risk of fetal distress. They found that both methods were equally safe for the induction of labor and misoprostol was actually more [66] effective.

Another method for ripening the cervix is by mechanical dilation. These devices may act by a combination of mechanical forces and by causing release of endogenous prostaglandins. Foley balloon catheters placed in the cervix, extra-amniotic saline infusions, and laminaria have all been studied and have been shown to be effective. Regardless of what method is chosen for cervical ripening, the practitioner must be aware of  the potential hazards surrounding the use of these agents in the patient with a scarred uterus. In addition, the potential for uterine tachysystole and subsequent fetal distress requires that care be taken to avoid using too high a dose or too short a dosing interval in an attempt to get a patient delivered rapidly. Care should also be taken when using combinations of mechanical and pharmacologic methods of cervical ripening. Once an induction of labor has begun, watch for the major potential complications associated with inductions beyond 41 weeks' gestation and have a plan for dealing with each. Complications include the presence of meconium, macrosomia, and fetal intolerance to l abor. The further the pregnancy progresses beyond 40 weeks, the more likely it is that significant amounts of meconium will be present. This is due to increased uteroplacental insufficiency, which leads to hypoxia in labor and activation of the vagal system. In addition, the presence of a smaller amount of amniotic fluid increases the relative concentration of meconium in utero. Traditionally, saline amnioinfusion and aggressive nasopharyngeal and oropharyngeal suctioning at the perineum were used to decrease the risk of meconium aspiration syndrome. Recent studies contradict this standard practice. Fraser et al performed a prospective, randomized, multicenter study evaluating the risks and benefits of amnioinfusion for the [41] prevention of meconium aspiration syndrome. They concluded that in clinical settings, which have peripartum surveillance, amnioinfusion of thick meconium-stained amniotic fluid did not decrease the risk of moderate-to-severe meconium aspiration syndrome, perinatal death, or other serious neonatal disorders compared with expectant management. In addition, other recent studies have shown that deep suctioning of the airway at the perineum does not effectively prevent meconium aspiration syndrome, contrary to popular belief. Fetal macrosomia can lead to maternal and fetal birth trauma and to arrest of both fi rst- and second-stage labor. Because the risk of macrosomia increases throughout term and postterm pregnancies, one of the most important parts of the delivery plan is being prepared for shoulder dystocia in the event that this unpredictable, anxiety-provoking, and potentially dangerous condition arises. To prepare such an event, experienced clinicians should be present at the delivery, a stool/step next to the delivery bed should be placed to help with suprapubic pressure, and the maneuvers to reduce the shoulder dystocia should be reviewed. Finally, intrapartum fetal surveillance in an attempt to document fetal intolerance to labor before it leads to acidosis is critical. Whether continuous fetal monitoring or intermittent auscultation is used, interpretation of the results by a well-trained clinician is of paramount importance. If the fetal heart rate tracing is equivocal, fetal scalp stimulation and/or fetal scalp blood sampling may provide the reassurance necessary to justify continuing the induction of labor. If the practitioner cannot find reassurance that the fetus is tolerating labor, cesarean delivery is recommended.