Length of pregnancy of Sri Lankan women attending a tertiary care center in Colombo.

Background & Objectives: The median time from ovulation to birth is estimated to be 268 days (38+2 weeks). However, there is a gestational length variation in the range of 37 days. Previous studies have shown that perinatal mortality and morbidity of the foetus increase after a period of gestation (POG) of 41 weeks due to increase in foetal size. It is also believed that South Asian foetuses have a shorter length of pregnancy and a higher risk of mortality when compared with Europeans. Induction of labour may be associated with increased risks of complications and higher expenses.
This study was designed to ascertain the length of uncomplicated pregnancy in Sri Lankan women and pregnancy outcomes of those managed expectantly till 41 weeks, as well as identify the cost associated with induction of labour and the safest and most cost-effective time period for induction of labour in Sri Lankan foetuses.
Methods: A descriptive cross-sectional study was conducted among 922 women who had uncomplicated singleton pregnancies with dates confirmed by ultrasound at 12-13 weeks at Colombo South Teaching Hospital. Routine antenatal care was offered.
Results: Out of the 922 pregnant women 93.16% (n=859) underwent spontaneous onset of labour by POG 41 weeks and 3 days. Only 6.83% (n=63) required induction with the expectant management policy. There were 29 (3.14%) Special Care Baby Unit (SCBU) admissions of which only 9 were after POG 40 weeks
Conclusion: A significant proportion of women with uncomplicated pregnancies underwent spontaneous onset of labour with minimum complications by POG 41+3 weeks. Both maternal and neonatal health were optimal. Induction of labour poses a risk to both the mother and the foetus and is an economic burden to under-resourced settings. Hence it is prudent that we fully understand that the true length of pregnancy may be longer than expected and allow spontaneous onset of labour to occur. Further studies need to be conducted to ascertain the true length of pregnancy beyond POG 41 weeks. A uniform policy for timing of induction of labour for Sri Lanka should be formulated by considering region specific data.