Does early growth delay occur in diabetic pregnancy?

OBJECTIVE

To identify the date of ovulation in pregnant women with Type 1 diabetes in order to assess the validity of the concept of early growth delay.

DESIGN

Identification of ovulation by measurement of urinary luteinising hormone and assessment of fetal growth using ultrasound scan.

SETTING

Diabetic pre-pregnancy and antenatal clinic in a teaching hospital.

SUBJECTS

Twenty women with Type 1 diabetes who had attended a pre-pregnancy clinic.

MEASURES

Urinary LH, by laboratory and kit methods, during conception cycles. Human chorionic gonadotrophin measured in early pregnancy. Early ultrasound scans by a single observer blind to menstrual and ovulation dates.

OUTCOME

Gestation calculated from ovulation date and gestation estimated from menstrual dates, compared with gestation at age indicated by early ultrasound scan.

RESULTS

When the date of ovulation was identified in 20 women with Type 1 diabetes there was no evidence of growth delay in any pregnancy. When gestation was estimated from menstrual dates there was apparent early growth delay in six pregnancies.

CONCLUSION

This study, together with others discussed, indicates that early growth delay is probably an artefact of incorrectly estimated ovulation date.