How does the process of conception work?

When a woman is ovulating, the egg is released from the follicle into the ovary and enters the fallopian tube. It starts its journey to the uterus when it is fertilized in about five days. If the egg is not fertilized it degenerates in forty-eight hours. When the sperm is inserted into the vagina it starts its way towards the egg. The sperm is a very tiny cell and exists from the head, midpiece and tail. Sperm contains both RNA and DNA carrying instructions for development of the embryo. Conception does not happen in the uterus, but in the outer part of the fallopian tube. The sperm is attracted to the egg by a chemical attractant. Sperm produces hyaluronidase, which dissolves the thin layer around the egg called zona pellucida. When an egg is fertilized it is called a zygote. In the first eight weeks the conceptus is called embryo and after that foetus.

What are the chances of conception and how can they be improved?

The most important way to improve conception is to have intercourse while the woman is ovulating. The best way to determine when a woman is ovulating is to measure body temperature. On the day of the ovulation the temperature drops, and the day after it rises again. Sperm can live in the woman’s body for five days meaning intercourse could also take place a few days before the ovulation. Also, regular intercourse (every day or every two days) is important for the male’s sperm count. The position of intercourse is important for an optimal flow of sperm into the vagina. Finally, lubricants should not be used as they might kill or block the sperm.

How does the conceptus develop?

The “silent struggle” between conceptus and pregnant woman is about the competition for nutrients. The placenta determines the flow of nutrients to protect the foetus. The months of pregnancy are divided into three parts, or trimesters. After conception and the passing through the fallopian tube, the single and now divided egg cell arrives in the uterus for implantation. During the first eight weeks, the major organ systems of the embryo are formed. The ectoderm will become the entire nervous system plus skin. From there it develops into the digestive -and respiratory system. The mesoderm will become the skeleton and muscles, but also the circulatory ad reproductive system. The head develops at first, followed by the body. This is called a cephalocaudal order.

The placenta exists from a lot of tissue and exists from the trophoblast. This is the tissue surrounding the conceptus and matures the growth. The circulatory systems of the woman and conceptus are separate. The placenta serves as a barrier between these two systems. It produces oestrogen and progesterone and many of the physical symptoms occurring while pregnant are because of these elevated hormones. The placenta also produces human chorionic gonatropin (hCG), this is the hormone detected with a pregnancy test.

The umbilical cord is developed in the fifth week of embryonic development. It is attached to the placenta in order to interchange substances between the woman and the foetus. The two membranes around the foetus are called chorion and amnion filled with amniotic fluid in which the baby can float. It keeps the foetus at a constant temperature and provides protection against possible injury.

How does the foetus develop?

The foetus develops the fastest in the first trimesters. At the end of the first trimester, the foetus looks human and the development consists of enlargement of already present structures. By the eighteenth week the woman can feel movement and heartbeat. The baby should be born about twenty weeks after that. The foetus should turn in the uterus after seven weeks. If this does not happen, the baby will be born in a breech presentation.

What are the stages of pregnancy?

Trimester I

The first trimester (until week twelve) starts with the detection of pregnancy. The body-temperature chart can provide insights into pregnancy. The body temperature stays up after ovulation for about two or three weeks. Other symptoms in early pregnancy are morning sickness, sensitivity of the nipples and tenderness of the breasts. Pregnancy tests should be taken as early as possible. The accuracy of a home-pregnancy test depends on the sensitivity to hCG. There are three signs of pregnancy, presumptive signs, probable signs and positive signs. Positive signs cannot be detected until the fourth month and include beating of the heart, movement and the detection of the foetal skeleton (by ultrasound). The expected delivery date (EDC) is calculated using nӓgele’s rule.

Physical changes during the first trimester include increased level of hormones, women urinate more frequently and the colour around the nipples turns darker. Also experiences of sleepiness and fatigue are common and caused by high levels of progesterone. Psychological changes vary with the attitude to the pregnancy. Social class also influences emotional state during pregnancy, where a low income can cause depression in pregnant women. Anxieties of women will often centre around miscarriage. The emotional state can influence the development of the foetus. Stress can cause stillbirth, the delivery of a death foetus. Intercourse is safe throughout the pregnancy. It is even related to a reduced risk of preterm birth.

Trimester II

In the second trimester (weeks thirteen to twenty-six) the woman is aware of the foetus’ movements. Most physical symptoms, such as morning sickness are down to a minimal level. Other physical problems arise, such as nosebleeds and constipation. Edema, or water retention and swelling can become a problem in hands and wrists. Around the middle of pregnancy, colostrum could already come out of the nipple, without milk. Psychological changes are that the woman becomes calmer, the discomforts of the first trimester start to disappear and the woman feels the movement of the foetus. Depression is less likely. Woman who experienced pregnancy before are more distressed than woman who did not.

Trimester III

The third trimester (weeks twenty-seven to thirty-eight) is characterised by the very large and hard uterus. The foetus is becoming more active and can keep the woman awake at night. The size of the uterus pressures other organs which can cause shortness of breath. Women often feel low on energy during this period. The amount of weight gain should be restricted because it can cause complications, the strain on blood pressure and the heart is much higher with women that gain an excessive amount of weight. During the third trimester, the uterus contracts painlessly, these contractions are called Braxton-hicks contractions. It helps to strengthen the uterus muscles for labour. The turning of the babies’ head and dropping into the pelvis is called dropping, engagement or lightening. Psychological influence comes from support during pregnancy. Women with less support in this period have a higher chance on a baby with a low birth-weight.

What is the experience of the father during pregnancy?

The father can experience pregnancy symptoms as well. This is called the couvade syndrome and are caused by hormonal changes in prolactin. In some cultures, the couvade ritual exists where the husband lays in bed while his wife is in labour. He suffers all the pains of delivery. Nowadays, men are expected to take an active part in fathering. A father instinct and bond to the child can be strengthened by the response to the infant. They also play a role in preparing for the baby, joint activities between partners increases the bond and provides a better foundation for their new family member.

What are the effects of substances on pregnancy?

A drug taken during pregnancy will also circulate through the body of the foetus. Drugs that may cause severe consequences are called teratogens. The drugs that women should be cautious about are the following:

• Antibiotics can cause severe defects during birth and can cause foetal abnormalities.

• Alcohol can cause any foetal alcohol spectrum disorder. The severity and occurrence depend on substance and occurrence. The foetal alcohol syndrome (FAS) is a malfunction with prenatal and postnatal (brain) growth deficiencies. The most serious effect of FAS is intellect, children with FAS score about 2 standard deviations below the average. There are no safe limits of alcohol consumption during pregnancy.

• Cocaine is related to the risk of premature birth and birth weight. Children exposed to cocaine can exhibit neurological defects and lower intelligence scores.

• Marijuana use can cause premature birth, reduces growth and reduced weight although the empirical evidence varies. Verbal skills and memory can be affected, but also hyperactivity, impulsivity and externalizing behaviour.

• Steroids also correlate to low birth weight but can also cause stillbirth.

• Other substances such as smoking causes cardiovascular disease or heart problems. The risk on asthma increases. The use of tricyclic antidepressants can result in birth defects, but the results are inconclusive. The use of psychiatric medication in general should be individually examined and discussed with a psychiatrist and an obstetrical services provider.

• Dads and drugs, drugs taken by the father even before conception may also cause birth defects. Drugs could damage sperm and its genetic content. A father who was smoking in the absence of the woman also increased the risk of childhood cancer.

What are the stages of labour?

Labour starts with contractions of the uterus. In ten percent of women, the water breaks. It means that the membranes with fluid rupture bursts. With most women, the sac does not break until the end of the first stage of labour. Contractions during labour are very irregular. The biological system causing labour to start is not completely clear. It could be a hormone that inhibits progesterone is released.

Labour often is divided into three stages:

1. First stage labour starts with the contractions and these cause two changes in the cervix. These are effacement, thinning out and dilation, opening up. The process of first stage labour consist of early first labour, late first stage labour and transition.

2. Second stage labour begins when the cervix is fully dilated. The head of the baby starts to move into the vagina or birth canal. With each contraction the baby can be pushed down and when the babies head can be seen it is called crowning. Many physicians perform an episiotomy, an incision in the skin behind the vagina. The incision prevents problems with later sexual functioning. After the first breath, the baby can be cut off from the placenta and the uterus of the mother.

3. Third stage labour is when the placenta comes loose from the wall of the uterus and the afterbirth is expelled. Contractions can be accompanied with the outburst of the placenta.

A caesarean section (c-section) is used when vaginal birth is impossible. Reasons could be that the vagina is too small, the labour has been very long and hard or the mother is near the point of total exhaustion. Other reasons could be that the health of the mother or baby is getting worse or the umbilical cord prolapses. Even though someone had a c-section, it does not mean vaginal birth after that is not possible.

What are the options for childbirth?

• Prepared childbirth by education about fears and relaxation techniques. The Lamaze method exists of controlled breathing and relaxation. There are numerous other exercises available to prepare for childbirth. It helped improve experiences, however unrealistic expectations could arise, especially for women having their first, or primiparas.

• The use of anaesthetics in childbirth had become common. A spinal block is used to relief pain in the first stage of labour. The epidural block numbs the body and may be given before a c-section. A pudendal block in and injection in the vaginal wall and gives pain relief short before delivery. It has some risks for the woman and the baby, but when a woman cannot control the pain, she should be able to request anaesthetics.
• Home birth versus hospital birth, home delivery is less stressful for the woman whereas if unforeseen emergency takes place, a hospital might be more comfortable and homebirth dangerous.

During the prenatal period most differences between men and women arise. This complex process is named: parental sexual differentiation. In this chapter the process of the menstrual cycle and sexual differentiation is discussed.

What does the postpartum period look like?

During the postpartum period (after childbirth) there are both physical and psychological changes happening to the woman. Attachment to the baby and sex with the partner also play an important role in the postpartum period.

• Physical changes include severe drops of hormones and exhaustion after labour.

• Psychological changes can include postpartum depression, a depression followed by the birth of a baby.

• Attachment to the baby begins even before the baby is born and feelings of nurturance increase after birth.

• Sex during postpartum can be impossible in the first period. After four months most couples resume intercourse as back to normal.

How does breastfeeding work?

The biological mechanisms of breastfeeding are based on two hormones, prolactin and oxytocin. Milk is produced a few days after delivery. It gives the baby high protein and temporary immunity to several diseases. Substances taken by the mother are transmitted to the infant through the milk. Breastfeeding is encouraged. The physical and mental health of the infant benefits greatly from breastfeeding.  

What problems can arise during pregnancy?

• An ectopic pregnancy is a misplaced pregnancy and happens when the egg implants in the fallopian tube instead of the uterus.

• In pseudocyesis (false pregnancy) signs and symptoms of pregnancy are happening without actual pregnancy.

• Pregnancy-induced hypertension has three serious conditions, the first hypertension, second is preeclampsia, an elevated blood pressure together with edema (fluid-retention) and proteinuria (urine with protein). It is related to foetal death and has serious implication for the woman such as vision problems. The third is eclampsia, where the woman goes into a coma or dies. These problems occur around the twentieth week of pregnancy and is a reflection of the struggle between mother and foetus for resources.

• Viral illness during pregnancy, for example measles cause fifty percent of infants to be born deaf or mentally deficient. A woman should get a vaccination before she gets pregnant. Herpes increases the risk of spontaneous abortion.

• Birth defects can be genetic or caused by taken substances during pregnancy. Two ways can examine possible birth defects: amniocentesis, where fluid around the baby is examined for defects, chorionic villus sampling (CVS) is a technique that takes a sample for cells and analyse them before birth.

• RH incompatibility when the babies blood type contains Rh+ while the mother has Rh-. It can cause stillborn of the baby or severe disabilities.

• Miscarriage (spontaneous abortion) is the termination of a pregnancy trough a natural cause. This does not include premature birth or induced abortion.

• Preterm birth is a major complication and happens when a baby is delivered before thirty-seven weeks. A premature infant is less likely to survive.

What are causes and treatment of infertility?

Infertility is the inability of a woman to give birth to a living child. It can be caused by both the female, such as by pelvic inflammatory disease (PID) or by the man by for example sexual transmitted diseases. There are several ways of treatment of infertility.

• Artificial insemination is when semen is placed artificially into the vagina, uterus or fallopian tubes. It is a means for getting pregnant without having intercourse.

• Sperm banks use sperm that has been frozen. For example, men can freeze their sperm for if they get cancer or a vasectomy and still have children later.

• An embryo transfer is done from one uterus to another and for women who can conceive but always miscarry. A surrogate mother is then used to carry the baby.

• Test-tube babies come from in vitro fertilization or IVF. The fertilized egg is implanted into the women’s uterus. It is also possible to freeze fertilized eggs, you get frozen embryos. The legal status is undergoing a debate because of the worry on embryo wastage.

• GIFT or gamete intrafallopian transfer is when sperm and eggs are inserted into the vagina together.

What is the development on gender selection?

There is much interest in techniques that can alter gender in unborn babies. However, there are many ethical consequences. The population balance might change drastically. There are wisdoms about how to conceive a boy, but research did not find any evidence to support certain claims. There are possibilities to manipulate the gender, but these techniques are still forbidden, expensive and risky.