The use of ART for treating the infertile couple is increasing. Pregnancy rates after ART have shown continuous improvement. Approximately 1 % of babies born in United States are conceived by IVF, with live birth rate of 28.3 % per cycle. However, in recent years out comes other than live birth rates have become an important focus of investigation. .
When counseling couple for an appropriate treatment, risks and complications of ART versus non-ART treatments should be considered.
Let us review some adverse out comes from ART.
Multiple gestation.
Much of the morbidity in children born after ART is the result of multiple gestation.
Multiple birth is the big challenge facing infertility specialists.
In modern society there is a trend towards delayed childbearing. Older women , who are already at increased risk of multiple gestation due to age, are at increased risk of being infertile and of using ART. In an effort to improve pregnancy rates, usually multiple embryos are placed in the uterus. Many patients with infertility also desire to have twins over singleton gestation as an out come of ART treatment.
With ART risk of conceiving with twins is 22 times higher and with triplets 50 times higher then in general population. Multiple births account for 17% of all preterm birth( delivery before 37 weeks of gestation ) and 26 % of very low birth weight infants ( less then 1500 grams ). Mostly due to multiple gestation, children born after IVF have been found to have increased risk of cerebral palsy and higher hospitalization rates. Maternal mortality and complications , such as hypertension, prolonged bed rest due to preterm birth, postpartum hemorrhage and cesarean deliveries are also increased in multiple gestation. There is an excess cost to the health care system due to multiple gestations.
Fertility specialists are aware of the problem. Advances in embryo culture and selection techniques have been made. There is a trend towards reduced number of embryos being transferred during IVF cycle.
Among patients with good prognosis ( younger then 35 years old and having extra embryos for freezing) single embryo transfer also results in high pregnancy rates and avoids the risk of multiple gestation.
Singletons conceived after ART.
There is suggestion that even singleton pregnancies are at higher risk for perinatal morbidity, including preterm birth and small for gestational age infants
Singletons conceived after IVF are at approximately 2-fold increase risk for perinatal mortality, low birth weight, very low birth weight, preterm delivery and small for gestational age infants. There is also possible increased risk for gestational diabetes, placenta previa, preeclampsia and stillbirth. There is an increased risk of induction of labor and cesarean delivery rate. The cause of these adverse out comes is unknown. Underlying disorder of infertile couple and some aspects of IVF treatment may be responsible.
4. Birth defects after ART
Increased birth defects after ART cycles have been reported. However, the effect is very small and further research is needed to determine the cause.
4. Birth defects after ICSI ( intracytoplasmic sperm injection )
Male partner is the cause or contributes to infertility in ab out 30 %- of cases Male infertility in many cases is associated with genetic abnormalities. Some couples who would be incapable of having baby due to severe male factor, now can conceive after ICSI. However, genetic abnormalities carried by Y chromosome can hypothetically pass to next generation males, although, at this time, children born from ICSI are too young to know there future reproductive performance.
Children born after ICSI may have slightly higher risk of birth defects than general population, but comparable to risk after ART with out ICSI. Reported higher birth defect rate might be from more careful evaluation and monitoring of these baby’s, problems inherent in the infertile population or unknown effect of treatment process.
It is important to keep in mind that the effect is very small if any but deserves further study.
5. Ovarian hyperstimulation syndrome.
On the maternal side, ovarian hyperstimulation syndrome is a complication of ovarian stimulation in luteal phase ( second half of cycle ) and early pregnancy. Mild forms are common ( up to 25 % of ART cycles ) and severe forms are rare ( 0.1-2%.). Syndrome is hard to predict, requires hospitalization and supportive care if severe. However, it is mostly self-limited process and strategies to lower the incidence include canceling cycle, not giving hCG ingection to release eggs, manipulating dose of medication, avoiding multiple gestation and cryopreserving embryos.
In summary, pregnancy rates continue to improve due to Assisted reproductive technology. Further research is required to understand short-term adverse out comes, long-term implications and to make ART safer for couples and babies.