Effects of in vitro maturation on physical development

This study examined whether conception associated with in vitro egg maturation led to any differences in height and weight development in children compared to those conceived through traditional in vitro fertilization.

Assisted reproductive techniques, such as in vitro fertilization (IVF), often involve the use of hormonal therapies to carefully control the timing of ovulation. However, in some women, particularly those with polycystic ovarian syndrome, hormonal therapies to induce ovulation of the mature egg can lead to ovarian hyperstimulation syndrome, a disorder which causes painful, swollen ovaries, with the possible complication of fluid accumulation in the abdomen or chest.

A newer treatment option, in vitro maturation, allows for the harvesting of immature follicles (eggs), thereby eliminating the need for ovarian stimulation. The immature follicles are matured and fertilized outside of the body, and the resulting embryo is implanted into the uterus, as with traditional IVF.

Because in vitro maturation is a relatively new treatment, very little is known about the development of children conceived using this method. The current study followed infants conceived after in vitro maturation for the first years of life, to determine whether the technique had an effect on height and weight.

In this study, 38 infants (22 boys, 16 girls) conceived after in vitro maturation to women with polycystic ovarian syndrome were compared to 38 infants (23 boys, 15 girls) conceived through traditional IVF. Height and weight measurements were compared at birth, 1 year of age and 2 years of age.

Girls conceived after in vitro maturation were found to be significantly heavier, with a higher body mass index (measure of body fat) at each age group. At birth, female infants were an average of 535 grams (1.18 lbs) heavier and 2.4 cm (0.94 inches) taller than females conceived with traditional IVF. At age 1, female infants were an average of 1.6 kg (3.5 lbs) heavier and 3.2 cm (1.25 inches) taller when conceived after in vitro maturation. At age 2, girls were an average of 1.3 kg (2.9 lbs) heavier when conceived after in vitro maturation, though the height difference was no longer significant. Body mass index was higher in females conceived after in vitro maturation at ages 1 (17.5 compared to 16.6) and 2 (17 compared to 15.9).

No significant differences were seen between boys conceived after in vitro maturation or traditional IVF.

This study concluded that girls conceived after in vitro maturation were significantly heavier and taller than girls conceived through traditional in vitro fertilization.

However, in this study, all women using in vitro maturation had polycystic ovarian syndrome, but none of the women in the in vitro fertilization group had this disorder. Therefore, it is impossible to determine whether or not polycystic ovarian syndrome played a role in the height and weight differences seen in these infants.