Science Fair Project Encyclopedia
Childbirth (also called labour, birth, or parturition) is the culmination of pregnancy, the emergence of a child from its mother's uterus. It is considered by many to be the beginning of a person's life, and hence the opposite of death. Age is defined relative to this event in most cultures. A woman is considered to be in labour when she develops regular painful uterine contractions, which are accompanied by changes of her cervix, these primarily being effacement and dilation. While childbirth is widely experienced as painful, some women do report painless labors.
The normal birth
The medical science of childbirth is obstetrics and a doctor who specializes in attending births is an obstetrician. Obstetricians are surgeons, who are trained to see childbirth as potentially pathological and in need of routine interventions. Midwives see childbirth as a normal event for most women, one which is best handled by as few interventions as possible. Midwives are trained to assist at births either through direct-entry or nurse-midwifery programs. Lay midwives are trained through being apprenticed to an experienced midwife.
First stage: contractions
A typical human childbirth will begin with the onset of contractions of the uterus. The frequency and duration of these contractions varies with the individual. The onset of labour may be sudden or gradual. A gradual onset with slow cervical change towards 3 cm dilation is referred to as the "latent phase". A woman is said to be in "active labour" when contractions have become regular in frequency (3-4 in 10 minutes) and about 60 seconds in duration. The now powerful contractions are accompanied by cervical effacement and dilation greater than 3cm. The labour may begin with a rupture of the amniotic sac, the paired amnion and chorion ("breaking of the water"). The contractions will accelerate in frequency and strengthen. In the "transition phase" from 8cm-10cm of dilation, the contractions often come every two minutes are typically lasting 70 - 90 seconds. Transition is often regarded as the most challenging and intense for the mother. Some mothers say things like "I give up, I want to stop now. Forget this!" It is also the shortest phase.
During a contraction the long muscles of the uterus contract, starting at the top of the uterus and working their way down to the bottom. At the end of the contraction, the muscles relax to a state shorter than at the beginning of the contraction. This draws the cervix up over the baby's head. Each contraction dilates the cervix until it becomes completely dilated, often referred to as 10+ centimetres (4") in diameter.
During this stage, the expectant mother typically goes through several emotional phases. At first, the mother may be excited and nervous. Then, as the contractions become stronger, demanding more energy from the mother, mothers generally become more serious and focused. However, as the cervix finishes its dilation, some mothers experience confusion or bouts of self-doubt or giving up.
The duration of labour varies wildly, but averages some 13 hours for women giving birth to their first child ("primiparae") and 8 hours for women who have already given birth.
If there is a significant medical risk to continuing the pregnancy, induction may be necessary. As this carries some risk, it is only done if the child or the mother are in danger from prolonged pregnancy. 42 weeks gestation without spontaneous labor is often said to be an indication for induction although evidence does not show improved outcomes when labour is induced for post-term pregnancies. Inducing labor increases the risk of cesarean section and uterine rupture in mothers that have had a previous cesarean section.
In the second stage of labour, the baby is expelled from the womb through the vagina by both the uterine contractions and by the additional maternal efforts of ("bearing down"). The imminence of this stage can be evaluated by the Malinas score.
The baby is most commonly born head-first. In some cases the baby is breech meaning either the feet or buttocks are descending first. Babies in the "breech" position can be delivered vaginally. Though in some areas finding an experienced willing attendant can be difficult.
There are several types of breech presentations the most common is where the baby's buttocks are delivered first and the legs are folded onto the baby's body with the knees bent and feet near the buttocks (full or breech). Others include Frank breech, much like full breech but the babies legs are extended toward his ears, and footling or incomplete breech, in which one or both legs are extended and the foot or feet are the presenting part. Another rare presentation is a transverse lie. This is where the baby is sideways in the womb and a hand or elbow has entered the birth canal first. A vaginal birth should not be attempted, although in rare cases the arm can be pushed back up and the baby can be physically turned into the proper position.
The length of the second stage varies and is affected by whether a woman has given birth before, the position she is in and mobility. The length of the second stage should be guided by the condition of the foetus and health of the mother. Problems may be encountered at this stage due to reasons such as maternal exhaustion, the front of the baby's head is facing forwards instead of backwards (posterior baby), or extremely rarely, because the baby's head does not fit properly into the mother's pelvis (cephalo-pelvic disproportion), true CPD is typically seen in women with rickets and bone deforming illnesses or injuries, as well as arbitrary time limits placed on second stage by caregivers or medical facilities.
Immediately after birth, the child undergoes extensive physiological modifications as it acclimatizes to independent breathing. Several cardiovascular structures start regressing soon after birth, such as the ductus arteriosus and the foramen ovale.
The medical condition of the child is assessed with the Apgar score, based on five parameters.
Third stage: placenta
In this stage, the uterus expels the placenta (afterbirth) and the mother normally loses less than 500ml of blood. It is essential that the whole placenta is expelled, so the midwife will examine the placenta to ensure that it is intact. Remaining parts can cause postnatal haemorrhage or infection.
After the birth
Immediate breastfeeding of the first milk termed colostrum is recommended to reduce postpartum bleeding/hemorrhage in the mother, and to pass immunities and other benefits to the baby.
Usually soon after birth the parents assign the infant its given names. They may have two names in mind, one for if it is a boy, and one for if it is a girl.
Often people visit and bring a gift for the baby.
Mothers often are allowed a babymoon period where they are relieved of their normal duties to recover from childbirth and establish breastfeeding with their babies. Length of this period varies. In China this is 30 days and is referred to as "doing the month".
When the amniotic sac has not ruptured during labour or pushing, the infant can be born with the membranes intact. This is referred to as "being born in the caul." The caul is harmless and its membranes are easily broken and wiped away by the doctor or midwife assisting with the childbirth. In medieval times, and in some cultures still today, a caul was seen as a sign of good fortune for the baby, in some cultures was seen as protection against drowning, and the caul was often impressed onto paper and stored away as an heirloom for the child. With the advent of modern interventive obstetrics, premature artificial rupture of the membranes has become common and it is rare for infants to be born in the caul in Western births.
Non-medical pain control
For some women the perceived pain of labor is a large concern. There are many ways to reduce the pain of labour, including psychological preparation, education, hypnosis, use of water in a tub or shower, emotional support and comfort measures by a trained professional Doula. These often offer good results and have no risks to the mother or baby. Many women find the reliance on analgesic medication unnecessarily unnatural (or feel it may harm the child); most of these agree to non-pharmacological measures to control the pain.
Medical pain control
In Europe, inhaled nitrous oxide gas is a commonly used measure of pain control; in the UK, midwives may use this without doctors' approval. Pethidine (with or without promethazine) may be used early in labour, as well as other opiates; if given too late, they may cause respiratory depression in the infant.
Popular medical pain control in hospitals include regional anesthetics (epidural or spinal anaesthesia); these are often used for pain control, and are a necessity for Cesarean surgery (unless a general anesthetic is used).
The various measures for pain control have varying degrees of success and side effects to mother and baby. Timing of the administration is often a concern. For example an epidural given too early in labor can stop or slow labor, given too late in labor can hinder maternal efforts to push out the baby.
Complications of birth
Complications occasionally arise during childbirth; these generally require management by an obstetrician.
Non-progression of labor (longterm contractions without adequate cervical dilation) is generally treated with intravenous synthetic oxytocin preparations. If this is ineffective, Caesarean section may be necessary.
Fetal distress is the development of signs of distress by the child. These may include rising or decreasing heartbeat (monitored on cardiotocography/CTG), shedding of meconium in the amniotic fluid, and other signs.
Non-progression of expulsion (the head or presenting parts are not delivered despite adequate contractions): this can require interventions such as vacuum extraction , forceps extraction or Caesarean section.
Heavy bleeding during or after childbirth is a potentially lethal complication, particularly in places without access to emergency care. Heavy blood loss leads to hypovolemic shock, insufficient perfusion of vital organs and death if not rapidly treated by stemming the blood loss (medically with ergometrine and pitocin or surgically) and blood transfusion. Hypopituitarism after obstetric hypovolemic shock is termed Sheehan's syndrome.
In modern times, participation of the father during childbirth is now the norm. However, before the 1960s, in most cultures the father was forbidden to enter childbirth area, as were other men with the exception of the doctor.
The recent social development of increased education, requiring signed consent, permitting fathers into the birth area, and leaving the mother with less impairment from drugs and physical restraint, has led to a considerable increase in parental involvement in all aspects the birth process. In recent years, many believe all of these social changes have allowed reductions in circumcision rates, along with drops in other often unnecessary and harmful interventions, such as episiotomy.
Many families view the placenta as a special part of birth, since it has been the child's life support for so many months. Many parents like to see and touch this mysterious organ. In some cultures, there is a custom to dig a hole and plant a tree along with the placenta on the child's first birthday. The placenta may be eaten by the newborn's family, ceremonially or otherwise.
The eldest American woman known to give birth was Arceli Keh, aged 63. In November 2004 Aleta St. James, a 56 year old single mother gave birth to twins conceived through in vitro fertilization. In 2005 a 67 year old Romanian woman gave birth by cesarean to one surviving twin.
Childbirth can be considered a stressful event. Some women report symptoms compatible with post-traumatic stress disorder (PTSD) after birth. Postnatal depression and postpartum psychosis develop is some women.
- Emergency Child Birth - Provides video clip and colour photos (real) of child birth, and also emergency measures
- How you came into the world and grew inside a womb: from cells and embryo to baby - Has colour photos (real) and explanations
- AP story on pregnancies in the elderly
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details