Association of the number of follicles of various sizes and treatment protocol with multiple pregnancies following ovulation induction and intrauterine insemination.

OBJECTIVE

To find the relationship between the number of follicles of different sizes and the stimulation protocol to the probability of multiple pregnancies.

METHODS

Out of 2034 cycles of OI-IUI in a university based infertility center, between March 2003 to March 2006, there were 322 clinically pregnant cycles. The following variables were tabulated for each cycle: female age, treatment protocol, follicle number and size on the day of hCG administration and number of gestational sacs detected by transvaginal ultrasonography at 9 weeks of gestation. Ovulation induction was done by cc, cc+hMG or hMG. Follicles were categorized by size as = 18mm, = 15mm and = 12mm. To find the relationship between singleton and multiple pregnancy with the average number of follicles of different sizes and the protocol of treatment, a statistical analysis was performed.

RESULTS

There were 38 (11.8%) multiple pregnancies in 322 pregnant cycles. consisting of 26 (8.1%) twin, 11 (3.4%) triplet and 1 (0.3%) quintuplet. Multiple pregnancy rate in cc, cc+hMG and hMG cycles were 9.01%, 12.2% and 15% respectively. There was no significant relationship between different treatment protocols and the risk of multiple pregnancy (p > 0.1). The number of follicles > or = 12 mm or > or = 15 mm or > or = 18 mm had significant relationship with single and multiple pregnancies (p < 0.01), but the correlation coefficient was higher for > or = 18 mm follicles. The mean age of the singleton and multiple pregnant women was not significantly different (p > 0.1).

CONCLUSIONS

The risk of multiple conceptions is related to > or = 18 mm follicles in addition to the total number of follicles >12 mm. Different protocol of ovulation induction revealed no relationship with the risk of multiple conceptions.