Effectiveness of first trimester ultrasound screening in reduction of postdated labor induction rate


  • Saugat Koirala Department of Obstetrics and Gynecology, Haamro Sahayatri Hospital, Kathmandu, Nepal
  • Achala Thakur Department of Obstetrics and Gynecology, BP Koirala Institute of Health Sciences (BPKIHS), Dharan, Nepal
  • Rubina Rai Department of Obstetrics and Gynecology, BP Koirala Institute of Health Sciences (BPKIHS), Dharan, Nepal
  • Baburam Dixit Thapa Department of Obstetrics and Gynecology, BP Koirala Institute of Health Sciences (BPKIHS), Dharan, Nepal
  • Ashok Raj Pant Department of Radiodiagnosis, BP Koirala Institute of Health Sciences (BPKIHS), Dharan, Nepal




Antenatal women, First trimester dating scan, Postdated pregnancy, Induction of labor


Background: The gestational age calculation by ultrasonography (USG) at first trimester is based on crown-rump length is more accurate, less erratic than last menstrual period based dating. Utilization of first trimester based scanning in dating the pregnancy will reduce the labor induction rate and consequently reduce the morbidity related to induction of labor.

Methods: A comparative cross-sectional study was done among 314 booked antenatal women visiting department of obstetrics and gynecology, BPKIHS for regular check-up between 37 and 41 weeks of gestation. Expected date of delivery was calculated from crown rump length (CRL) of the first trimester scan for USG group while last menstrual period was taken to calculate expected date of delivery for LMP group and were called for induction at 41 weeks of gestation. The rates of labor induction, emergency cesarean section (CS) among induced group, indication of CS and mode of delivery were compared in both the groups.

Results: There was 14% labor induction rate in USG group and 24.2% in LMP (last menstrual period) group and differed significantly (p=0.022). There was no difference in the mode of delivery among participants in either groups. The rate of emergency CS among women undergoing induction of labor was 54.5% and 39.5% respectively for USG and LMP groups (p=0.258). Overall, non-reassuring fetal heart rate was the most common indication for CS in both the groups.

Conclusions: The finding suggests first trimester scan among all pregnancies will reduce the post-dated inductions, as well as need of CS.



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Original Research Articles