INDUKSI PERSALINAN pada KEHAMILAN 41 MINGGU

Post Dates Induction of Labor

Di Kamar Bersalin , seorang pasien berusia 39 tahun , primigravida dengan usia kehamilan 41 minggu dirawat di rumah sakit atas indikasi INDUKSI PERSALINAN pada KEHAMILAN POSTMATUR

Kehamilan berlangsung normal tanpa komplikasi, tanggal perkiraan persalinan dipastikan melalui pemeriksaan USG trimester pertama. Keterangan ini penting sebab, banyak kasus “postdatisme” sesungguhnya adalah “wrong datisme” dan pasien baru pertama kali datang ke rumah sakit setelah merasa bahwa kehamilannya tak kunjung berakhir dengan persalinan.

Setelah kehamilan mencapai 36 minggu, fungsi plasenta mencapai “plateau” atau bahkan sudah mulai akan “berkurang”. Oleh karena plasenta normal mempunyai kapasitas cadangan yang besar, maka penurunan fungsi diatas tidak akan menimbulkan masalah , kecuali bila memang kehamilan terus belanjut sampai lebih dari 2 minggu dari tanggal tafsiran persalinan. Diantara sejumlah kasus kehamilan postdate, banyak terlihat adanya bukti penurunan fungsi plasenta seperti PJT-pertumbuhan janin terhambat – oligohidramnion dan “meconium” staining.

Jangan membiarkan usia kehamilan sampai melampui 41 minggu. Pada kehamilan 41 minggu, usaha untuk mengakhiri kehamilan harus sudah dilakukan. Namun masalahnya, banyak kasus kehamilan mencapai usia kehamilan 41 minggu dengan servik yang masih belum matang atau “unfavourable cervix” sehingga kemungkinan keberhasilan induksi persalinan sangat rendah. Akibatnya adalah, sejumlah induksi berlangsung terlalu lama dan meningkatkan resiko infeksi.

Untuk menghindari komplikasi tersebut, dapat pula dilakukan monitoring janin serial dengan NST-non stress test, evaluasi ultrasonografi untuk melihat abnormalitas janin, oligohdramnion dan profil biofisikal sambil menunggu servik menjadi matang. Perlu disadari bahwa monitoring diatas bersifat pasti dalam menentukan ada tidaknya disfungsi plasenta

Seringkali induksi persalinan dilakukan bahkan pada servik yang belum matang sebagai upayta untuk mencegah makrosomia yang menyebabkan distosia bahu dan cedera pleksus brachialis pada neonatus oleh karena janin dapat terus tumbuh dan berkembang karena fungsi plasenta masih berjalan normal.

Pada kasus ini, servik masih belum matang (oui tertutup – tebalnya 2 cm – kaku – mengarah ke posterior dan bagian terendah janin stasion -3). Dokter memberi kesempatan 1 hari untuk maturasi servik dengan memberikan misoprostol selama 12 jam dan diikuti dengan induksi persalinan. Selama 12 jam, terjadi perubahan servik (dilatasi 2 cm, pendataran 1cm, lunak dan mengarah ke bagian tengah). Mulai diberikan induksi persalinan dan respon pasien bagus dengan kontraksi uterus setiap 3 menit dan masing-masing kontraksi berlangsung selama 60 detik . Pola persalinan berlangsung normal dan janin dalam keadaan sehat.

Di Kamar Bersalin, untuk mematangkan servik dapat digunakan Kateter Balon (balon digelembungkan dengan air agar terjadi dilatasi mekanis pada servik) dan irigasi perlahan pada segmen bawah rahim sehingga dapat terjadi maturasi servik dalam waktu 6 jam.

Dilatasi mekanis ini tidak selalu menyebabkan proses pematangan molekuler seperti yang terlihat pada penggunaan misoprostol, sehingga cara ini jarang digunakan.

 

 

 

Here in Labor and Delivery we have Candace Scoville. Candace Scoville is a 39 year old G-1 at 41 0/7 weeks gestational age, here for induction of labor because of post-date pregnancy.

She had an uncomplicated pregnancy, with her due date confirmed by first trimester ultrasound. This is important because many cases of “post datism” are actually cases of “wrong datism”.

As pregnancy advances past 36 weeks, placental function plateaus or even starts to diminish. Because the normal placenta has great reserve capactity, this loss of placental capabilities is usually not a problem, unless the patient goes way past their due date. Among some post date pregnancies, we can see evidence of reduced placental function, including fetal growth restriction, oligohydramnios and meconium staining.

One common approach to this issue is to not allow pregnancies to persist beyond a certain cut-off date, such as 41 weeks. After that, labor is induced. Of course, the main problem with this approach is that not all patients at 41 weeks will have a favorable cervix for induction. Consequently, some of these inductions take a very long time, with some increase in the cesarean section risk and the risk of infection.

To avoid those complications, some providers generally induce patients who cross the 41 week mark, but will hold off on the induction if the cervix is generally unfavorable.

Another approach is increased monitoring of the fetus with serial non-stress testing for fetal well-being, ultrasound evalauation to detect fetal growth abnormalities and oligohydramnios, or biophysical profiles. While this approach avoids the problem of inducing unfavorable cervices, none of our monitoring systems is perfect and watchful expectancy will not totally avoid the problem of placental dysfunction.

Some providers prefer induction of labor, even in the face of an unfavorable cervix, in order to decrease the risk of excessive fetal size, which can predispose toward shoulder dystocia and brachial plexus injury to the newborn. This preference is based on the knowledge that fetuses continue to grow larger throughout pregnancy and termination of the pregnancy at term will disallow further growth. There are some problems with this line of thinking.

While it’s true that fetuses continue to grow, they don’t grow much after 38 weeks, with their maximum rate of growth of ½ pound a week seen around 32 weeks of pregnancy. The incremental growth after the 40th week is quite small. So for induction of labor to be effective in reducing delivery weight of the baby, induction would have to be initiated around 36-37 weeks. By waiting until 41 weeks, we would have waited too long…the baby is already big. But initiating delivery at 36-37 weeks creates too much risk of prematurity to be justified for routine avoidance of fetal macrosomia, so it is not done.

In the case of this patient, she had an unfavorable cervix for induction (closed, 2 cm thick, firm, posterior, with the presenting part at -3 station). Her physician opted to bring her in at 40 1/7 weeks for cervical ripening with misoprostol for 12 hours, followed by pitocing for induction of labor. During those 12 hours, her cervix has changed from closed, 2 cm thick and firm, to soft, 2 cm dilated, 1 cm thick, and mid-position. We have started pitocin and she’s responding well, with contractions every 3 minutes, lasting about 60 seconds. The baby is tolerating this labor pattern normally.

We also could have used an EASI catheter, a balloon-tipped catheter that is threaded through the cervix and then inflated. The pressure of the catheter balloon, combined with slow irrigation of the lower uterine segment with normal saline, would be expected to dilate the cervix to several cm dilatation over the course of 6 hours. However, this forcible dilatation does not always cause the molecular ripening that we see with misoprostol, and in this case, we did not employ the technique.

About Bambang Widjanarko

Obstetrician and Gynecologist ; Staf pengajar di Fakultas Kedokteran & Kesehatan UMJ ; Kepala Departemen Obstetri Ginekologi FKK UMJ ; Ahli Kebidanan & Ilmu Penyakit Kandungan di RS Islam Jakarta Utara.

Posted on 02/05/2012, in Uncategorized. Bookmark the permalink. Leave a comment.

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