All about the baby-making process
As children, most of us grew up believing all kinds of stories about where babies came from. As adults we may know as much that they are a result of a sperm meeting an ovum, yet few us really know much more than that. So wheredo babies come from? If you’re planning for a child, or have just become pregnant, and looking to understand better the baby-making process of nature, here’s some information you’ll be glad to know.
ConceptionHere you will find everything you need to know about how babies are conceived
The ovum is a female reproductive cell, or egg. By the time a baby girl is born, one to two million eggs are in her ovaries, two small oval organs situated on either side of the uterus or womb. Many of the eggs die before she reaches puberty, and only about 400 eggs are released during her lifetime. The eggs are released, on average, once every 28 days throughout her fertile years. A woman is fertile typically between the age of 12, the average age when she is likely to get her period, and 52, the average age when she is likely to hit menopause.
Conversely, male sperm is continuously being produced during his lifetime, and takes about three months to mature as an adult reproductive cell. Healthy sperm is produced at 34 degrees celsius, 4 degrees less than the average body temperature, which is why the testicle sac hangs outside and away from the body. Sperm can live up to a few weeks inside a man’s body, and about 40 million of them are on an obstacle race to fertilise an egg each time a man ejaculates – only about a dozen will make it to the egg and only one sperm can fertilise an egg. The sperm will determine the sex of the baby: sperm with a Y chromosome will make a boy baby, and sperm with an X chromosome will make a girl. The male and female sex cells contain 23 chromosomes (genetic material) each, so that their fusion forms a single cell that contains 46 chromosomes. That said, if you feel that you can’t cope, or if you’re feeling sad and hopeless, or if you’re having thoughts about harming yourself you should call your doctor immediately
Each month, the ripest of up to three eggs reaching maturity in one of the ovaries is released. An egg is released from an alternate ovary each month, and ovulation is usually 12-14 days before a period. When the egg is released, it is sucked into the fallopian tube to begin its 10 cm journey to the uterus, and should be fertilised within 24 hours for a new life to begin. It may take a sperm anything from 45 minutes to 12 hours to swim from the cervix to the fallopian tubes. If the sperm don’t find an egg in the fallopian tubes, they can survive for up to seven days, meaning that you could still conceive if you ovulate within this time window. When the egg is fertilised by a sperm, it changes so that no other sperm can get in. The fusion of the male and female reproductive cells produce a one-celled organism known as a zygote, which immediately begins a two-week period of rapid cell division to become an embryo and then a fetus.
The zygote divides through a process known as mitosis, whereby each cell doubles by dividing into two cells. After about five days, the mass of cells becomes known as a blastocyst, and after about fourteen days, the embryonic period will begin. This is all happening as it moves slowly through the fallopian tube to the uterus. This two-week stage is known as the germinal period of development from the time of conception to the implantation of the embryo in the uterus, where it must implant in the lining in order to obtain the nourishment it needs to grow and survive.
Several hormones are in play each month for ovulation to take place – such as the luteinizing hormone (LH), follicle-stimulating hormone (FSH), oestrogen and progesterone. In a male, the hormone in play is testosterone. If conception occurs, a pregnancy hormone known as hCG will be present in the mother’s blood and can be detected in a pregnancy test usually 3 to 4 weeks from the first day of the last period.
If conception does not take place, the ovary stops making oestrogen and progesterone, the two hormones that would maintain a pregnancy. As the levels of these hormones drop, the thickened lining of the uterus is shed, along with the unfertilised egg, during your period.
A woman may get her period — and become fertile — any time between the ages of 8 and 15. A woman’s fertility is at its peak in her 20s, gradually starting to reduce in her late 20s. By the time she reaches her 30s, it starts to drop more quickly — by about 3 percent per year — until she is 35, and then at a faster rate after that. The greatest risk of waiting until the late 30s to get pregnant is the difficulty of getting pregnant in the first place, particularly after the age of 40, while women rarely get pregnant after the age of 45. Most women reach menopause between the ages of 45 and 55, but menopause may occur as earlier as the 30s or 40s, or may not occur until a woman reaches her 60s. The onset of menopause is not related to the age when a girl begins to have menstrual periods.
Men’s fertility is less affected by age. They may father children well into the ages of 60, 70 or even 80! However the chances of getting their partner pregnant is reduced and, as men get older, the quality of their semen declines in volume and quality. They have fewer and slower-swimming sperm, while the shape (morphology) of the sperm also declines in quality, all factors which make the sperm less likely to fertilise the egg. Shape is particularly important because it gives an indication of the sperm’s genetic content.
Risks of late pregnancy
If you are over 35 and planning to get pregnant, speak to your doctor to explore the chances of certain increased risks to yourself and the baby. For the baby, chances of chromosomal or other birth defects may increase, as well as lower birth weight. For the mother, there are higher risks of high blood pressure, gestational diabetes or preeclampsia (high blood pressure, protein in the urine, or liver or kidney abnormalities) during pregnancy. There is also an increased risk of placental problems, such as placental abruption (where the placenta prematurely separates from the uterine wall) and placenta previa (where the placenta lies low in the uterus, partly or completely covering the cervix), or even an ectopic pregnancy (where the placenta implants outside the womb). All these risks exist in any pregnancy, however risks do increase with age. Some birth defects, such as restricted growth (achondroplasia) and downs syndrome have been correlated with the older age of the father, however these risks are greater if both parents are over 35.
Perimenopause — the time leading to menopause when the first symptoms may appear — can begin up to ten years before the actual menopause, when menstruation ceases and your chances of becoming pregnant naturally stop. During the perimenopause years, the ovaries become less and less active and oestrogen and progesterone levels fall, giving rise to various uncomfortable symptoms such as hot flushes, night sweating, sleep disorders, mood swings, memory lapses, vaginal dryness, itchy skin, irregular periods, loss of libido, hair loss and incontinence, among others. These symptoms can be alleviated – speak to your doctor.