All pregnancies can be risky, but there are greater risk for women who are older and are over the age of 40. The older the women the riskier the pregnancy. As women get older, they are more likely to suffer from conditions such as gestational diabetes and pre-eclampsia. If older women do conceive over the age of 40, their offspring may be of lower birth weight, and more likely to requires intensive care. Because of this, the increased risk is a sufficient cause for concern. The high incidence of caesarean in older mothers is commonly regarded as a risk.

A body mass index (BMI) over 27 causes a 33% decrease in likelihood to have a live birth after the first cycle of IVF, compared to those with a BMI between 20 and 27.[29] Also, pregnant women who are obese have higher rates of miscarriage, gestational diabetes, hypertension, thromboembolism and problems during delivery, as well as leading to an increased risk of fetal congenital abnormality.[29] Ideal body mass index is 19–30.[17]
Anger, sadness, and anxiety are common among parents struggling to expand their family. "Having a child already doesn't make going through infertility any easier," says Alice D. Domar, Ph.D., executive director of the Domar Center for Mind/Body Health, in Waltham, Massachusetts, and author of Conquering Infertility. Meeting with a mental-health professional or seeking out blogs and online groups for secondary infertility can help. The website of  the National Infertility Association, resolve.org, is a good place to start.
Ovarian stimulation – You’ll take stimulation medications to increases both the quantity and quality of eggs. This usually begins during days 2-4 of your cycle and continues for around ten days. You’ll be closely monitored during this time to track your uterine lining, follicular development, and hormone levels. Once the follicles are optimal size, a trigger medication is given to fully mature the eggs.
These time intervals would seem to be reversed; this is an area where public policy trumps science. The idea is that for women beyond age 35, every month counts and if made to wait another six months to prove the necessity of medical intervention, the problem could become worse. The corollary to this is that, by definition, failure to conceive in women under 35 isn't regarded with the same urgency as it is in those over 35.
While I’m not on the list to receive a Nobel Prize for mathematics any time soon, I do have enough understanding of how probabilities work to know that roulette isn’t a very viable long term career choice. Figuring that if I could make this costly error in analysis, there must be at least a few others out there that have, or will, make the same mistake as me…
At RMA, once the embryos reach the blastocyst stage, they are tested through a process called Preimplantation Genetic Testing for Aneuploidy (PGT-A), which lets doctors know which embryos have a normal number of chromosomes. While genetically normal embryos are much more likely to lead to pregnancy and healthy babies, the transfer of abnormal embryos will either result in no pregnancy, miscarriage, or an affected baby. While testing is occurring on a small part of the embryos, the embryos themselves are frozen, awaiting a receptive uterus. A large, prospective study performed recently at RMA confirmed that performing an embryo biopsy does not harm the embryo and does not decrease the likelihood of implantation.
The second study by Huang et al. demonstrated nearly equivalent pregnancy rates between the three medications. Furthermore, the twin risk was not significantly elevated in any of the three groups. The key difference between these studies is that the dose of gonadotropins was higher in the AMIGOS study (150 units) than the Huang study (75 units). A higher dose often means more eggs ovulated and a greater risk of twins or more.
A study presented at the British Fertility Society Annual Conference and covered by The Guardian reported that transferring two embryos where one is of poor quality would reduce the chance of pregnancy by 27%. It is thought that a bad embryo is rejected by the endometrium, compromising the implantation of both embryos. Cumulative research has supported the notion that egg quality outweighs quantity.

Intercourse must take place frequently, particularly before and around the time of ovulation, and the couple must have been trying to conceive for at least one year (6 months if the woman is over 35 years old). Using these criteria, about 10-20% of all infertile couples have unexplained infertility. However, the percentage of couples classified as having unexplained infertility will depend upon the thoroughness of testing and the sophistication of medical technology. 
No matter how many times you've been asked, "When will you have another baby?" the query still stings. Try coming up with a quick comeback—like 'We actually love having an only child'—and commit it to memory, says Dr. Davidson. Another heartbreaker: your child's pleas for a sibling. Try, "You're so wonderful we don't need anyone besides you." Or maybe admit, "We'd like nothing more than to make you a big brother. We hope it'll happen."
^ Baker VL, Luke B, Brown MB, Alvero R, Frattarelli JL, Usadi R, et al. (September 2010). "Multivariate analysis of factors affecting probability of pregnancy and live birth with in vitro fertilization: an analysis of the Society for Assisted Reproductive Technology Clinic Outcomes Reporting System". Fertility and Sterility. 94 (4): 1410–6. doi:10.1016/j.fertnstert.2009.07.986. PMID 19740463.
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