Difference between serum beta-human chorionic gonadotropin levels in pregnancies after in vitro maturation and in vitro fertilization treatments

Objective: To compare β-hCG levels measured as the first pregnancy test in women who conceived after in vitro maturation (IVM) or IVF. Design: Retrospective matched cohort analysis. Setting: University-based medical center. Patient(s): Women treated with IVM or IVF. Intervention(s): We studied the first serum β-hCG levels in 104 pregnant women who were successfully treated with IVM and in another 104 women with IVF treatment. Blood samplings for β-hCG were drawn on day 12-15 after ET. The two groups were matched by age, order of pregnancy, and day of blood sampling. Main Outcome Measure(s): First β-hCG levels. Result(s): Serum β-hCG levels on days 12 to 13 after ET of IVM viable singleton pregnancies were significantly higher than those of IVF pregnancies (343.2 ± 48.4 vs. 264.0 ± 29.2 IU/L, 95% confidence interval [CI] 22-229). Similarly, β-hCG levels on days 14 to 15 after ET of IVM viable singleton pregnancies were higher than those of IVF pregnancies (350.1 ± 126.4 vs. 284.4 ± 30.2 IU/L). Similar trends were found in β-hCG levels on days 12 to 13 after ET of twin viable pregnancies (IVM, 682.1 ± 97.7 vs. IVF, 434.5 ± 41.8 IU/L; 95% CI 44-662). Grouped linear regression with covariance analysis showed a significant difference between IVM and IVF regression lines. Conclusion(s): The first serum β-hCG levels in pregnancies after IVM are consistently higher than those after IVF treatment. More studies are needed to elucidate these findings.