Age remains one of the most important factors influencing women fertility. Research shows that fertility declines steeply after age 35. However, with modern technology and medical knowledge, the likelihood of getting pregnant after 35 is higher than before.
The age at which you conceive or decide to conceive is a very personal decision. In Hong Kong, more and more couples start a family later in life. According to the Census and Statistics Department Hong Kong (pg.32), the median age at first childbirth rose from 26.6 years in 1986 to 31.6 in 2017.
While today women are delivering healthy babies throughout their 30s and beyond, traditionally 35 and older is considered a high-risk pregnancy. In obstetrics expectant mothers who are 35 or over are referred to as “Elderly Primigravida” for a first pregnancy and “Elderly Multigravida” for having been pregnant more than once. Other terms associated with being pregnant after 35 are “advanced maternal age” and “geriatric pregnancy”.
We take a closer look at prenatal care and childbirth after 35 with Dr. Alexander K. Doo 杜堅能醫生, Obstetrician-Gynecologist from The Women’s Clinic – Dr. Doo discussed the matter in depth back in October 2018 at the Healthy Matters Maternity + Baby Event, as one of our featured speakers.
Why is 35 considered a downhill number when it comes to pregnancy? When was it chosen, and does it apply to everyone in their mid-thirties and older?
The number 35 was defined more than 30 years ago and some would argue that age by itself should not be major criteria for high-risk. For example, a 39-year-old woman could be healthier than a 29-year-old. However, as you get older, you are more likely than younger women to have certain health conditions that can cause complications before and during pregnancy.
Also, the chance of conception declines with age, and at 35 the success rate is halved compared to a woman at her peak fertility. The quality of the eggs also declines, and therefore the risk of chromosome abnormalities is also increased.
What are the higher risks for expectant moms after 35 (e.g. miscarriage)?
Risks or complications that may occur before and during pregnancy for women 35 and over include:
- Fertility problems
- Miscarriage risks
- Preexisting diabetes
- Gestational diabetes
- High blood pressure
- Premature birth
- Low birthweight
- Being pregnant with multiples – both naturally and with fertility treatment
- Chromosomal abnormalities, for example, Down syndrome
- Fetal congenital anomalies
- Placental abruption
- Caesarean section (the older you are, the more likely you are to have pregnancy complications that make a C-section necessary)
- Stillbirth rates increase at an older age: 18 to 34 – stillbirth rate of 4.7 per 1,000 or 0.47%; 35 and 40 – stillbirth rate of 6.1 per 1,000 or 0.61%; 40 and older – stillbirth rate of 8.1 per 1,000 or 0.81%.
How is prenatal care different after 35? Will I be seeing my doctor more often?
In general, the ante-natal visit is similar to others, provided that all is going well, and no particular risk factors are identified. This means 4 weekly visits until 28 weeks, 2 weekly visits till 36 weeks, and then weekly after that. Should you have particular risks factors, then more frequent monitoring would be advised by your doctor.
What are the recommended genetic tests for pregnant women 35 or older?
Older women are more likely to have a baby with chromosome abnormalities, so you will be advised to have some prenatal tests to check. For example, the rate of an embryo having Down syndrome at the 10-week mark of pregnancy is 1 in 1,064 at age 25, whereas it rises to 1 in 686 at age 30 and 1 in 240 by the age of 35 years. At the age of 40, the Down syndrome rate increases to 1 in 53, and down to 1 in 19 embryos at age 45.
Screening tests, like cell-free fetal DNA screening check for chromosome abnormalities via a blood test from the mother. However, it is still a screening test and if it is positive you would still need to do amniocentesis to confirm.
What are the recommended diagnostic tests for pregnant women 35 or older? What are the risks of these diagnostic tests?
In the old days, before cell-free DNA testing, a CVS or Amniocentesis would be routinely offered to all mothers over 35 years old as these are diagnostic tests of chromosome problems that the baby may have, but it carries about a 1% risk of miscarriage or damage to the fetus. With the development of NIPT (non-invasive prenatal testing), most people would first be offered this as a screening test and would only proceed to invasive testing if the result is positive, or markers for genetic disease is noted during scanning, as it has no risk to the baby and the mother. However, it must be remembered that this is still a screening test and may have false positive and negative results.
What are childbirth risks and how can they be prevented? (i.e. increased risk of complications during delivery: prolonged labor, assisted delivery, C-section, or stillbirth).
In order to reduce the complications of childbirth, we need to start from pre-conception. Your doctor may suggest lifestyle changes and address any chronic diseases that may affect your pregnancy and the baby’s health.
Other prevention methods include:
- Attend prenatal care regularly to help monitor both baby and your health.
- Eat a healthy diet and take daily prenatal vitamins which may help to supplement the additional folic, calcium, iron, and vitamin D required in pregnancy.
- Regular physical activity can help prepare for labour by increasing your stamina and muscle strength.
- Avoid alcohol and tobacco.
- To reduce the increased risk of stillbirth at term, consider induction of labour at about 39 weeks.
- In order to prepare the perineum and reduce tearing, exercise the pelvic floor> or use devices such as an EPI-NO to stretch the perineum.
- Try to tail off (or reduce top-up dose) the epidural towards the end near full dilatation to try and improve the sensation of the urge to push, this would help to reduce the chances of instrumental delivery.
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