Abstract
Introduction
Term pregnancy is defined as pregnancy lasting between 37 completed weeks and 41 weeks + 6 days. Pregnancy that reach or continue beyond 294 days (42weeks) are described as post terms. Prolonged pregnancy is between 41 – 42 weeks and occurs in approximately 5 – 10% of pregnancies. The estimated date of confinement or due date for normal pregnancy is calculated as 38 weeks after conception or 40 weeks after first day of normal LMP (assuming 28 days menstrual cycle). The Commonest cause is error in calculation of gestational age. Nulliparity, advanced age, obesity are the strongest risk factors. Before deciding the best course for the management of prolonged pregnancy it is imperative to reconfirm the gestational age by a dating scan performed in first half of pregnancy. Increasing availability of USG has significantly improved accuracy of pregnancy dating and detection of fetal anamolies, so extremely long gestations are rare. WHO recommends a policy of routine induction of labor at 41 completed weeks. An earlier induction can potentially expose the mother to a greater risk of operative intervention and subsequent morbidity, while delaying induction increases chances of fetal distress and perinatal morbidity.
References
- Tenore JL. Methods for cervical ripening and induction of labour. Am Fam Physician. 2003 May 15;67 (10):2123-8.
- Savitz D, Terry JW, Dole N, Thorp JM, Siega-Riz AM, Herring AH. Comparison of pregnancy dating by LMP, ultrasound scanning and their combination. Am J Obstet Gynecol 2002;187:1660-6
- World Health Organization. WHO recommendations for induction of labour. Geneva: World Health Organization;2011.
- Brouwers HAA, Bruins HW, van Huis AM, de Miranda E, Ravelli ACJ, Tamminga P. Netherland: Perinatal Registration Netherlands (PRN) 20104.
- Johnson DP, Davis NR, Brown AJ. Risk of caesarean delivery after induction at term in nulliparous women with an unfavourable cervix. American journal of obstetrics and gynecology. 2003 Jun 30;188(6):1565-72.
- Macer JA, Macer CL, Chan LS. Elective induction versus spontaneous labor: a retrospective study of complications and outcome. American journal of obstetrics and gynecology. 1992 Jun 30;166(6):1690-7.
- Vrouenraets FP, Roumen FJ, Dehing CJ, van den Akker ES, Aarts MJ, Scheve EJ. Bishop score and risk of caesarean delivery after induction of labor in nulliparous women. Obstetrics & Gynecology. 2005 Apr 1;105(4):690-7.
- Cole RA, Howie PW, Macnaughton MC. Elective induction of labour: a randomised prospective trial. The Lancet. 1975 Apr 5;305(7910):767-70.
- Heimstad R, Skogvoll E, Mattsson LA, Johansen OJ, Eik-Nes SH, Salvesen KA. Induction of labor or serial antenatal fetal monitoring in postterm pregnancy: a randomized controlled trial. Obstetrics & Gynecology. 2007 Mar 1;109(3):609-17.
- Hermus MA, Verhoeven CJ, Mol BW, de Wolf GS, Fiedeldeij CA. Comparison of induction of labour and expectant management in post term pregnancy: a matched cohort study. J midwifery Womens Health 2009, 54(5):351-356.
Corresponding Author
Dr Poonam Kumari
PGT 2nd year, Dept. of Obstetrics & Gynaecology, KMCH