IVF success in a cohort of very young women

Abstract

To evaluate the success of In Vitro Fertilization in a cohort of very young women. Retrospective chart review. We examined the incidence of positive pregnancy tests as well as clinical intrauterine pregnancy rates in a cohort of women undergoing In Vitro Fertilization at a single IVF center in Utah over a period of 5 years (2010-2014). Success rates were compared based on a woman’s age at the start of her cycle. Very young women were considered to be age less than 24 years at the start of their cycle. These women were compared to their slightly less young counterparts age 24-34 years. Success rates were defined as follows: positive pregnancy was defined as an hCG level >5mIU/mL 10 days after blastocyst transfer or 12 days after cleavage stage transfer. Clinical intrauterine gestation was defined as the presence of at least one gestational sac with a fetal pole and cardiac activity noted on ultrasound at or after 6.5 weeks gestation. Number of embryos transferred, BMI and smoking history were also compared between the age groups. Variables were compared using Chi square or t-test as appropriate. From the period of January 1, 2010 to December 31, 2014 a total of 2,157 IVF cycles were initiated at a single IVF clinic in Utah. Of these, 1,457 were completed in women age <35. Complete data was available for 1,325. Positive pregnancy for the entire cohort was 63.1% (836/1325), while the incidence of clinical intrauterine gestation was 55.3% (732/1325. The percentage of cycles leading to a clinical intrauterine gestation in women age <24 was 32.4% (35/108) versus 57.3% (697/1217) in women age 24-34 (p<.001). There was no difference between the groups in the number of embryos transferred (1.84 vs. 1.91, p=NS) or in current or past tobacco use (2.7% in both groups, p=NS). Interestingly, there was a statistically significant difference in mean BMI between the groups; women age <24 had a mean BMI of 22.6 (95% CI 21.9-23.4), whereas women age 24-34 had a mean BMI of 24.4 (95% CI 24.1-24.7, P=0.001). The clinical significance of this finding is uncertain, as both ranges fall within a healthy weight BMI category. In this cohort of women undergoing IVF, very young women had significantly lower success rates when compared to their slightly older counterparts. Further evaluation is indicated as appropriate counseling of patients is critical. Consideration should also be made for changing SART-reported age groups.