Clinical strategies to avoid multiple pregnancies in assisted reproduction

Multiple birth rates of Korea and fetal/neonatal/infant mortality in multiple gestation

Objective

This study was conducted to analyze recent trends of multiple birth rates (MBR) and fetal/neonatal/infant mortalities according to the number of gestations in Korea.

Methods

Data from 2009 to 2015 of live births, infant deaths and stillbirths were obtained from the Korean Vital Statistics. Neonatal mortality rate (NMR), infant mortality rate (IMR), and fetal mortality rate (FMR) in singleton, twin and triplet pregnancies were analyzed according to gestational period (GP; ≤ 23, 24–27, 28–31, and 32–36 weeks).

Results

From 2009 to 2015, twin and triplet birth rates increased 34.5% and 154.3%, respectively. In twin births, NMR and FMR have been decreased significantly (from 10.92 to 8.62, p = 0.034 and from 41.00 to 30.55, p< 0.001, respectively), but IMR did not show significant decrease. There was no significant change of NMR, IMR, and FMR, in triplet births. Overall, in singleton, twin, and triplet births, NMR was 1.26 ± 0.09, 10.6 ± 1.12, and 34.32 ± 11.72, respectively, and IMR was 2.38 ± 0.26, 14.52 ± 1.38, and 41.13 ± 12.2, respectively. FMRs were 12 ± 1.73, 35.99 ± 3.55, and 88.85 ± 16.55, respectively, in singleton, twin, and triplet pregnancies. In spite of decreasing trends in overall mortalities, the odds ratios of NMRs and IMRs in 2015 were approximately 9-fold and 6-fold higher, respectively, in twin births, and approximately 37-fold and 20-fold higher, respectively, in triplet births, than those in singleton births. There were no significant differences in odds ratios of NMRs and IMRs at GP 32–36 among single, twin, and triplet births, although the odds ratios of FMR at GP 32–36 in triplet gestation was significantly higher than those in singleton and twin gestation.

Conclusion

Neonatal/infant mortality in multiple births is still significantly high, which is mainly related with preterm birth. Close fetal monitoring is needed to prevent fetal death in triplet pregnancies, after 32 gestational weeks.

Predictors of twin pregnancy after ovarian stimulation and intrauterine insemination in women with unexplained infertility

Multi-foetal gestation is a well-known, adverse outcome of infertility treatment. Maternal and obstetrical complications are more frequent in multiple pregnancies compared to singletons. The aim of this study was to determine parameters that affect the risk for multiple pregnancies after ovarian stimulation (OS) with intrauterine insemination (IUI). We retrospectively evaluated all cases of OS with IUI cycles that ended with successful clinical pregnancy. A total of 259 pregnancies were analysed (175 singletons, 63 twins and 21 triplets). Significant parameters predicting multiple pregnancies were gravidity and number of follicles at least 15 mm in diameter on day of hCG. A previous pregnancy increased the risk for multiple gestation by a factor of 1.86 (95% CI 1.03-3.37, p = 0.04). Each follicle ≥15 mm increased the odds ratio for multiple gestation by 1.3 (95% CI 1.03-1.65, p = 0.027). In conclusion, women with more than one previous pregnancy and three or more than three follicles ≥15 mm at hCG are at risk for multi-foetal pregnancy after OS and IUI.

Multiple pregnancies following assisted reproductive technologies--a happy consequence or double trouble?

The association between assisted reproduction technologies (ART) and multiple pregnancy is well-established, with a multiple birth rate of 24% in ART pregnancies. Multiple pregnancy is associated with significantly increased maternal and perinatal morbidity and mortality, as well as increased costs to the National Health Service. Evidence relating to the obstetric outcomes of ART twins versus naturally conceived twins is discussed in this review. Methods to reduce the risk of multiple births including elective single embryo transfer and multifetal pregnancy reduction are also discussed.

Reluctance of medical professionals in adopting natural-cycle and minimal ovarian stimulation protocols in human clinical assisted reproduction

Recent clinical evidence would suggest that natural cycle and minimal ovarian stimulation protocols in clinical assisted reproduction could be advantageous for younger women with indications for either male-partner or mild female-factor subfertility. The benefits include reduced medical fees associated with lower or nil dosages of recombinant gonadotrophins, a shorter treatment cycle and reduced risk of ovarian hyperstimulation syndrome. Additionally, there is also evidence to suggest improved quality of retrieved oocytes and better endometrial receptivity. Nevertheless, fertility clinics and doctors have conflicting interests that make them reluctant to incorporate natural-cycle and minimal stimulation protocols in their treatment programme. Firstly, the use of low or nil dosages of recombinant gonadotrophins would drastically cut profits from drug prescription sales to patients. Secondly, fertility clinics are also concerned by the apparent reduction in success rates for natural-cycle and minimal ovarian stimulation protocols. Moreover, refunding of medical bills by health insurance is usually based on a limited number of attempts, thereby hampering the introduction of natural-cycle and minimal stimulation protocols, which have lower efficacy on a per cycle basis. Lastly, the adoption of natural-cycle and minimal stimulation protocols would drastically reduce the numbers of surplus oocytes and embryos available for donation to other patients.