Abstract
The time of ovulation and conception of 24 insulin-dependent (Type I) diabetic women was estimated by monitoring the basal body temperature (BBT). The mean (±SD) duration of the menstrual cycle was 28 (±2) days. Conception occurred, on the average, on the 18th day of the cycle. The fetal crown-rump length was measured by ultrasound scan every 2 weeks between 6 and 14 weeks of pregnancy. When menstrual history was used for dating, there was an apparent early fetal growth delay by a mean of 4 days. When the dates were corrected by BBT, the fetal growth was identical with the standard mean crown-rump length diagram by Robinson & Fleming. The findings of our study suggest that early fetal growth delay reported by Pedersen & Melsted-Pedersen does not exist in diabetic pregnancy. The small fetuses observed could be explained by an error in the gestational age.