Late parenthood: making it safe

Delayed parenthood requires careful handling from the point when couples are contemplating pregnancy through to navigating the course of high-risk pregnancies. TAN SU YEN reports

POSTPONING parenthood into the late 30s and 40s certainly has its practical advantages. Husband and wife are often well-established professionally, their financial portfolios are ship shape or getting there, they own a decent home and after a decade or more of self-fulfilment, couple time and seeing the world, they finally feel ready to become parents.

Nature, however, doesn't always deliver on demand as evidenced by the many cautionary tales of infertility among older parents. Obstetricians and gynaecologists will also point out that infertility is just one of the possible complications confronting older parents. Women who delay child-bearing into their late 30s and 40s risk miscarriage, difficult pregnancies and delivering babies with a higher risk of birth defects and chromosomal abnormalities.

Doctors classify a mother who is aged 35 or older at the time of delivery as being of 'advanced maternal age' or AMA for short. The majority of AMAs or older mothers do carry their pregnancies through to full term and give birth to normal, healthy babies. Still, a pre-pregnancy screening to rule out any possible problems or better manage them is recommended for older would-be mums.

Says Dr Julianah Abu-Wong, consultant obstetrician and gynaecologist, Pacific Specialist Practice, a member of Pacific Healthcare: 'If everyone goes for pre-pregnancy screening that would be ideal but if a woman is under 35, and has no medical problems, no family history of a genetic disorder like thalassemia, and if her husband is also very healthy, a simple pre-pregnancy screening with a GP would suffice.

'However, comprehensive pre-pregnancy screening with careful monitoring under specialist care, is beneficial for women who are older as they generally have a higher maternal and foetal risk. There are times when things can happen in pregnancy and during delivery and since we have so few deliveries and so few pregnancies, every pregnancy and every mother counts.'

Women with a family history of medical conditions or those who have a pre-existing condition themselves would also benefit from pre-pregnancy screening. Says Dr Wong: 'Take pre-existing medical conditions like diabetes, thyroid or depression - all these conditions involve medical treatment for the disease to be controlled well and medications tailored appropriately as a woman prepares for pregnancy.'

Even seemingly innocuous medication can have far-reaching implications that the patient is unaware of. Says Dr Wong: 'A patient may be on oral retinoids or vitamin A for her skincare or she may be taking tetracycline for acne and she doesn't even think to mention this to her gynaecologist. But these are things we try to pick up during the pre-pregnancy screening because tetracycline can cause discoloration of the teeth in the baby and retinoids can lead to a cleft lip or a cleft palate.'

Essential examination
A pre-pregnancy screening typically begins with a consultation followed by a physical examination, including a breast examination. The breast examination is essential, Dr Wong points out, as 'pregnant women do get breast cancer and women have an increased risk of breast cancer especially after the age of 40'. What follows is a urine analysis, a full blood count, a Pap smear, screening for rubella immunity, hepatitis B, HIV and sexually transmitted diseases as well as the pelvic ultrasound.

Dr Wong explains: 'A pelvic examination can pick out pelvic infections and cervical cancer and the pelvic ultrasound scan can detect existing gynaecological conditions such as fibroids and endometriosis. This allows us to address these conditions and manage them before the patient gets pregnant.' For example, fibroids, which are benign muscular growths in the uterus, may be a hindrance to pregnancy. One in five women of childbearing age are believed to be affected by fibroids, which are most prevalent
among women who are over 40.

Dr Wong notes: 'Fibroids that affect fertility are those that are found in the cavity as they can lead to a miscarriage or prevent implantation. Large fibroids and intramural fibroids or those in the uterine walls may also affect pregnancy because they can degenerate, cause pain or obstruct labour as the foetus descends through the pelvis during labour.' The latest approach to treating fibroids is to first shrink them through hormonal adjunct therapy before performing minimally invasive key-hole surgery to remove the fibroids.

Dr Wong says: 'The intracavitary fibroids can be removed by using a hysteroscope inserted through the cervix, while the others can be removed via key-hole or laparoscopic surgery using special instruments inserted through several small openings in the abdomen. The newest technique is the Da Vinci Robotic-Assisted Myomectomy where the enhanced 3-D view and technical manipulations allow large fibroids to be removed easily. Patients usually recover well enough to go home the next day after surgery and can try and get pregnant one to three months after fibroid surgery.'

Once the happy news of a pregnancy is confirmed, the priority shifts towards ensuring that the pregnancy progresses smoothly and that the baby is growing normally and well. This is where the First Trimester Pregnancy Screen (FTPS) is especially helpful, particularly for older parents.

Says Dr Ann Tan, consultant obstetrician and gynaecologist, Women & Fetal Centre, a member of Pacific Healthcare: 'FTPS is a non-invasive test that is safe for both mother and foetus. It is a screening test, not a diagnostic test, which means we comb through the population to pick out those at high risk. Not every expectant mother wants to know about her risk factors but I believe that every single mother should be offered FTPS so that if it is her wish, she can be accurately informed about her risks.'

The FTPS combines a high-resolution ultrasound scan with maternal blood screening and is performed late in the first trimester of pregnancy, that is from weeks 11 to 14. Among other things, FTPS measures what is known as nuchal translucency (NT) which is thickness of the fluid at the back of the baby's neck. An increase in NT thickness serves as an indicator of chromosomal disorders.

FTPS works by combining the results of the ultrasound and the blood test to detect 90 per cent of Down syndrome using an internationally proven and recognised computer alogorithm. Other common trisomies 13 and 18 as well as structural birth defects can also be screened for at the same time.

Down syndrome is a particular worry for older parents as the risk of having a baby with Down increases with age, in fact the risk increases exponentially after 35. Medical statistics indicate that a 30-year-old woman in her 12th week of pregnancy has a 1 in 626 risk of Down syndrome; a 35-year-old has a risk of 1 in 249 while a 40-year-old has a risk of 1 in 68.

Dr Tan explains: 'The various markers used in FTPS give a risk score which indicates whether the patient has a risk that is higher or lower than expected for her age group. For the most part, patients do get good news. For example, I recently had a patient in her forties whose risk factor for Down based on her age was 1 in 49. Her FTPS results revealed that her actual risk was 1 in 1,000. This shows that while she is in her forties, her body is behaving like that of a woman in her twenties and that is very good news indeed.'

But what if the results of the FTPS don't look good? What is the next step for anxious parents? Dr Tan says: 'If the scan or the blood test reveals that unfortunately, this looks like a high-risk pregnancy, then we take things to the next step which is to do a diagnostic test. The beauty of doing a detailed scan at 12 weeks is not only to pick up Down but to also detect other structural abnormalities in the baby such as an anencephaly where the baby has no skull.'

Follow-up diagnostic tests
One of the follow-up diagnostic tests that Dr Tan is referring to is the Chorionic Villus Sampling or CVS in which a sample of placental tissue is tested for chromosomal abnormalities and other genetic problems. The other diagnostic test is the amniocentesis in which a small sample of amniotic fluid is used for diagnosis.

However, an amniocentesis can only be performed at 16 weeks while the CVS can be performed immediately following the abnormal FTPS result thus reducing the wait and the anxiety. In large published studies there has been no difference in the procedure related loss risk from either of these procedures.

Says Dr Tan: 'Rapid tests can be performed with the conventional tests to allow us to obtain specific results in 24 to 28 hours. This spares the parents from days of nail-biting and gives them time to absorb the news and prepare themselves for the road ahead. In the difficult situation where there is a lethal abnormality, that is the baby will not survive even if carried to full term, it is essential for the parents and the doctor to have the necessary chromosomal confirmation in hand before exploring any definitive measures.'

In the majority of cases, however, FTPS results reveal that all is well with the baby. To date in Singapore, the combined FTPS tests have been performed on about 4,000 patients. Says Dr Tan: 'FTPS is good as a universal test. In the majority of cases, it serves to reassure mums and dads that they are going to have a normal, healthy baby. Once they know this, they can relax and enjoy the pregnancy as a happy, natural event.'

Delivering hope for high-risk couples

Infertility problems loom large for those aged 35 and older, which is why it makes sense for them to opt for fertility screening. TAN SU YEN investigates

THE average fertile couple has about a 20 per cent chance of conceiving each month. Within a year of trying, 80 to 90 per cent of them will achieve pregnancy.

Two categories of prospective parents, however, would do well to consider fertility investigations before the one-year mark - those who suspect they may have underlying medical problems and those where the woman is over 35 years old.

Dr Lee Wei Hong, consultant obstetrician and gynaecologist, MD Specialist Healthcare, a member of Pacific Healthcare, says: 'Medical problems that affect fertility would be present as symptoms that include irregular cycles, which indicate possible ovulatory disorders, painful menstrual periods or intercourse, which indicate endometriosis, and a history of pelvic infection.' The risk of infertility increases for women over 35 and rises even more dramatically for those over 40. Age also affects male fertility but to a lesser extent.

Dr Lee says: 'As women age, their eggs grow old with them, leading to problems with ovulation and fertilisation. Even when fertilisation is successful, older mothers are more likely to suffer a miscarriage as the uterus may be less receptive and as the incidence of gynaecological conditions like fibroids and endometriosis is higher among women in their late 30s and 40s.'

At the most fundamental level, infertility specialists like Dr Lee investigate the following when they suspect a couple is infertile: first, whether ovulation is occurring and if it is occurring at the right time; secondly, whether the sperm produced are normal, and thirdly, whether the egg and the sperm are able to meet so that fertilisation can take place. These investigations into a couple's fertility involve a battery of tests, including a clinical examination, a pelvic ultrasound scan, a blood test to determine hormonal profile, as well as tests on the fallopian tubes and the uterine cavity as well as sperm and urinary analysis.

The tests help doctors to zoom in on the possible causes for fertility while pointing towards how these problems may be addressed. The pelvic ultrasound scan allows doctors to determine if the endometrium or uterus lining achieves its optimal thickness to support implantation at about day 14 of the menstrual cycle. A lining that is too thin is problematic for implantation while a lining that is too thick predisposes the patient to polyps, impairing implantation. Similarly, a blood test that reveals abnormally high hormone levels or a reversal in their ratios reflects problems with ovulation. Once the cause of infertility is established, the next course of action is to correct the underlying medical problems, after which couples can move towards assisted fertility.

As a first step, clomiphene, a drug that triggers follicle-stimulating
hormones (FSH), may be administered to encourage egg growth and ovulation. In cases of male infertility, such as when the sperms have poor motility or are not well formed, and in situations when infertility is related to cervical factors, intra-uterine insemination is performed. By inseminating the sperms in the uterus, this technique bypasses the cervix, dispensing with its related obstacles. If these steps fail, couples then move further along the treatment ladder to in-vitro fertilisation (IVF). With IVF, the eggs are harvested from the ovary and combined with sperm in the laboratory. Seventy-two hours later the embryos are transferred into the uterus.

The ultimate assisted reproductive technique currently available is
intracytoplasmic insemination (ICSI). Dr Lee explains: 'With ICSI, very little is left to chance, as we inject the sperms directly into the egg almost immediately after retrieval. In this way, we maximise the chances of successful fertilisation and implantation.'

Not all couples choose to take a step-by-step approach to assisted reproduction. Dr Lee says: 'Proper counselling is important because some couples have a very strong and urgent desire for pregnancy and opt for the most advanced techniques at the outset. Other couples are willing to try simpler methods first and wait to see how they fare before moving on.'

Copyright © 2005 Singapore Press Holdings Ltd. All rights reserved.

Source: Business Times, 8 September 2006