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Sonographic dating of pregnancies conceived after contraceptive pill therapy
Author(s) -
Waldenström U.,
Axelsson O.,
Nilsson S.
Publication year - 1993
Publication title -
ultrasound in obstetrics and gynecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.202
H-Index - 141
eISSN - 1469-0705
pISSN - 0960-7692
DOI - 10.1046/j.1469-0705.1993.03010023.x
Subject(s) - medicine , bleed , biparietal diameter , obstetrics , pregnancy , gynecology , ultrasound , pill , surgery , gestational age , radiology , biology , head circumference , genetics , pharmacology
A total of 358 women succeeded in conceiving in the first cycle after stopping oral contraception. The estimated day of delivery was calculated from both an ultrasonographically measured fetal biparietal diameter, in the second trimester, and from the date of the withdrawal bleed. According to the biparietal diameter measurement, the estimated day of delivery was postponed more than 1 week in 138 cases (38.5%). For 304 women who delivered after the spontaneous onset of labor, the biparietal diameter estimate gave the best prediction of the day of delivery in 175 cases (57.6%), the date of the withdrawal bleed gave the best estimate in 91 (29.9%) ( p < 0.001) and they were equally good in 38 (12.5%). The estimated day of delivery using a biparietal diameter measurement was within ± 14 days of the day of delivery for 267 of these 304 women (87.8%). The corresponding figure for the withdrawal bleed date was 218 (71.7%) ( p ≤ 0.001). According to the withdrawal bleed date estimate, 68 women (22.4%) delivered beyond the estimated 42 weeks, compared to only 2.6% according to the biparietal diameter estimate. The median length of a pregnancy from the first day of the withdrawal bleed was 286 days and from the biparietal diameter was 281 days. Copyright © 1993 International Society of Ultrasound in Obstetrics and Gynecology