Labour and birth – Birthing in the ’90s: part 2

Labour and birth – Birthing in the ’90s: part 2 – includes related article on breech birth

Birthing in the ’90s

After nine months of intrauterine development, the fetus finally emerges to greet its parents as a newborn child. Where and how to give birth is an individual choice. While there are many birthing or “lying-in” centres in the U.S. – and calls for similar facilities here – at present, most Canadian births take place in hospital a method favoured by physicians because of instant access to services and equipment.

Amid mounting criticism of “medicalized” childbirth, most hospitals now try to mute the clinical surroundings and provide a softer, friendlier birthing atmosphere. Some hospitals have set up birthing units that simulate the cosy decor of a home environment. “Walkabouts” during first-stage labour are widely promoted – to aid uterine contractions. Breastfeeding is encouraged, and many newborns “room in” around the clock to help get breasffeeding off to a good start.

“At the McMaster Medical Centre,” says one obstetrician, “nurses now do much of the first-stage labour care. We’ve long ago stopped routine enemas and use of stirrups (except in problem births). Instead of the flat-on-the-back delivery position, with the mother working against gravity to push the baby out, women are encouraged to give birth in any chosen position – sitting, squatting or even standing – with the father sometimes cutting the cord (if he wants to).” Mothers are often discharged 24 to 48 hours after birth, if all goes well. Shorter maternity stays reduce the risk of infection, enhance family closeness and are cheaper. However, the shorter stay sometimes means that new mothers leave hospital without learning much about newborn care or breastfeeding.

The three stages of labour

The process that triggers labour is not yet fully understood. The first stage begins as the uterus contracts and the cervix, or neck of the uterus, begins to open. The mucus plug that fills the cervix is dislodged as the “show” – a small pinkish blob-that often heralds the start of labour, but may precede it by several days.

The first stage of labour usually lasts 12-18 or more hours in first-time mothers, and less, perhaps only 4-6 hours, in subsequent births. The fetal heart rate is checked regularly-babies at risk may be electronically monitored throughout labour – and the mother is occasionally examined internally to see how labour is progressing. There’s a gradual increase in the frequency, strength and duration of uterine contractions which feel somewhat like very strong menstrual cramps. The contractions dilate the cervix, ultimately to 10 centimetres (about four inches) – wide enough to let the baby’s head through. The sac that holds the water or amniotic fluid usually ruptures before full dilatation, towards the end of the first stage, but the waters often “break” sooner, even before contractions start. Early membrane rupture needs prompt auention as it breaks the sterile bag of water around the fetus, increasing infection risks and can trigger a premature labour.

The second stage of labour begins once the cervix is fully dilated and is often accompanied by an irresistible urge to push – symbolizing the woman’s active participation in labour. As the baby passes through the birth canal, the mother bears down, taking deep breaths. Birth attendants assist the baby’s emergence. The baby may be placed on the mother’s abdomen and allowed to suckle fight after birth. The sucking stimulates release of the hormone oxytocin, helps to contract and close up the uterus and may speed expulsion of the placenta. The third stage of labour, expulsion of the placenta or “afterbirth,” may take place up to half an hour later.

Birthing aids and procedures

Painkillers and/or anesthetics in labour are currently used by over half the Canadian women who give birth in hospital. An epidura! or spinal block, given by hypodermic injection, eases labour pain without dulling the woman’s awareness. Another strategy often used to ease discomfort in labour is entonox (or “laughing gas”). The woman holds the mask herself and breathes in the gas – the hand-held mask automatically falling off in case she takes too much!

Electronic monitoring of the fetal heartbeat during labour is almost routine in many North American hospitals. A belt strapped over the mother’s abdomen records the baby’s heart pattern, which is displayed on a screen. The fetal heart rate can also be monitored with a small electrode placed on the baby’s head. However, routine electronic fetal monitoring is now roundly criticized. Many experts believe that unless it’s done in conjunction with fetal scalp blood sampling (to measure fetal blood oxygen), electronic monitoring is “no better than using a stethoscope.” Even if done together with fetal scalp sampling, electronic heart monitoring can be unreliable. As one specialist notes “the results may be interpreted by inexperienced staff, producing false alarms of fetal distress in perfectly healthy babies, perhaps resulting in a cesarean.”

Induction of labour – inducing the uterus to start contracting with synthetic hormones such as oxytocin and prostaglandin E, or by breaking the bag of waters (or both) – takes place in about 15 per cent of Canadian births, compared to three to five per cent in many European centres. Valid reasons for induction may include: an overdue or “post-mature” baby, a diabetic mother with an unusually large baby or a mother in trouble-perhaps with eclampsia or a blood incompatibility. But any induction requires extra careful monitoring of maternal and fetal wellbeing.

Managing post-mature or “overdue” births. About 10 per cent of pregnancies go beyond the due date, sometimes up to 42 weeks. Those that go two or more weeks past the due date are considered “post-mature” and may encounter problems through an aging or failing placenta or a baby’s head that’s grown too big to pass through the woman’s pelvis. Therefore, post-term pregnancies are managed either by elective induction or by awaiting spontaneous labour, meanwhile carefully monitoring fetal wellbeing and inducing labour at any hint of fetal distress.

Episiotomies – making a cut in the vaginal wall to widen the passage and then sewing it up again – used to be almost routine for North American deliveries. But the procedure is now under fire as studies suggest it may be causing or worsening the very problems that it’s supposed to prevent (such as vaginal tearing, future laxity of the pelvic floor, bladder problems, incontinence and painful intercourse).

The piece of birth: home versus hospital

Home births remain an emotional and controversial issue, discouraged by the Canadian Medical Association, the Canadian Society of Obstetrics and Gynecology and agencies in many other western countries. Home births in Canada are attended mainly by midwives, with few physicians willing to assist. Some branches of the College of Physicians and Surgeons forbid physicians to attend home births because of “unnecessary risks to mother and infant.” In Canada only 0.9 per cent of women gave birth at home in 1991 (some of them unplanned), compared with 1.7 per cent in Britain and 30 per cent in Holland. Although about one third of births in Holland still occur at home, those who opt for home birth must have low-risk pregnancies and pass a rigorous selection process.

The argument against home birth focuses on the fact that it may subject mother and/or baby to avoidable risks and that even in seemingly healthy, normal pregnancies things can go wrong at the last minute. Some low-risk women who opt for home birth have to be transferred to hospital because of unforeseen events – such as hemorrhage, non-progression of labour (prolonged second stage), baby in an unsuspected breech (buttocks-first) position or a malpositioned placenta. In one study of over 1,000 low-risk, planned home births in Toronto between 1983 and 1988, 83 per cent proceeded normally, 17 per cent required transfer to hospital and two infants died. The study found the transfer rate of planned home births to hospital three times higher in first-time (primipara) pregnancies than in subsequent ones. Experience shows that most emergency birthing situations can be handled by a well trained birth attendant at home or that transfer to hospital can be arranged in time to avoid risks to mother or baby. Midwives carry some emergency equipment and will arrange for speedy transfer to hospital if needed. “But for a few emergencies,” notes one obstetrician, “such as serious fetal distress, the probable survival time is only 12-25 minutes-possibly too short for safe transfer.”

Nonetheless, at a recent pregnancy care conference, a Nottingham statistician declared that “for normal uncomplicated labours in England, large hospitals are the least safe places of birth – with an increased incidence of jaundice, forceps deliveries, asphyxia (from labour drugs) – and certainly less safe than small maternity units staffed mainly by general practitioners and midwives.” Another British survey concluded that “the setting, environment and type of obstetric care greatly influence birth outcomes and that the spill-over of medical knowledge to the home setting may make it a good situation for normal pregnancies at no anticipated risk. Hospital delivery is still best for pregnancies at known risk.”

At labour, unexpected problems may arise such as “failure to progress” (sluggish labour), an awkward fetal position, cord prolapse (a cord slipping down and cutting off the baby’s oxygen), a placenta that blocks the baby’s passage, cord wrapped around the baby’s neck, maternal hemorrhage or fetal distress. Such unanticipated problems underlie the rationale for giving birth in hospitals, where help is instantly on hand. Risk scoring 10 detect high-risk pregnancies

“Risk scoring” is a technique used to determine whether mother or fetus is in a risk bracket that might require referral to a specialized unit for safer birthing. A prenatal “score chart” plots maternal changes as they appear and estimates possible risks. About 10-15 per cent of all pregnancies pose some danger to mother, fetus or both at labour or birth and about 70 per cent of these are predictable in advance. Risk factors that are obvious or predictable include: maternal obesity, epilepsy, hypertension, diabetes, a narrow pelvis, heart problems or other medical disorders in the mother, previous premature or problem labors, an “incompetent” cervix, mother on drugs or poorly nourished. Additional risks that may surface as pregnancy advances include a prematurely separating or failing placenta, pre-eclampsia (with raised blood pressure and swelling of hands and face), early membrane rupture (“waters breaking”), an infection (e.g., by herpes or beta-streptococci), and – most feared of complications – a very premature labour.

From fetus to newborn: a big leap

At term, the average baby is about 20 inches (50 cm) long and weighs about seven and a half pounds (3500 grams). The passage out through a heaving birth canal brings immense changes for the fetus. Within minutes, it must change from being an aquatic creature, cushioned in a warm, dark, sterile bag of fluid, obtaining oxygen and food from the mother’s bloodstream, to being a self-sustaining, air-breathing baby. Newborns must start breathing with the lungs – a new exercise, albeit one already rehearsed in the uterus. In full-term newborns, the body is plump, most biochemical systems and enzymes are ready for action, the tiny lungs are coated with surfactant (a substance vital to lung expansion) and the chest is able to take that crucial first gasp of air. (The labour contractions may help to stimulate and get the newborn lungs working.) But in premie babies the lungs may not yet be fully developed and mature enough for air-breathing.

Premature and low birthweight babies

Perinatal units can now save smaller and smaller babies – the cut-off point for survival currently being about 24 weeks. At present, in Canada about five per cent of live births are premature – born before 36 weeks of gestation. Although premature or low birthweight babies are more vulnerable than full-term ones and may have to spend time in a neonatal unit, many happily survive. Nonetheless, the more premature or underweight the newborn, the greater the risk of health problems. The infant’s premature body may not have the fat reserves needed to bridge the gap until mother’s milk comes in a few days after birth. And the lungs of premature infants are often imperfectly prepared for air-breathing because they aren’t yet coated with surfactant, a substance that is crucial to lung function.

Small wonder that caregivers will do everything in their power to keep pre-term babies safely inside the uterus (perhaps hospitalizing a mother in danger of premature labour) rather than let a fetus with immature lungs out to attempt air-breathing. Modem drugs, given to a mother about to experience premature labour, can help to prepare immature fetal lungs and decrease the risks. But the reduced ability to withstand temperature changes, respiratory problems, infection and other hazards still puts premies at greater danger than full term babies.

In one Canadian study, of 260 infants born between 23-28 weeks of gestation, one third died. Those who did survive had above-average risks of physical and mental disabilities. In another study on surviving premies born at 24-29 weeks of gestational development, 80 per cent developed normally without handicap, about five per cent suffered severe disabilities (such as cerebral palsy and learning problems) and 15 per cent had mild disabilities. Low-birthweight but full-term babies who weigh less than average for a given developmental age (“small for date” or “small for gestational age” babies) also have fewer than average reserves with which to combat infections and they face increased risks of hearing, vision and learning problems. The World Health Organization defines low birthweight as “below 2,500 g (less than 5 1/2 lbs) at delivery;” very low birthweight as “less than 1,500 g (3 1/2 lbs).” Neonatal units now encourage parents to help look after premature or ailing newborns, to see and handle their infants, even if it simply means putting a hand into the incubator to stroke the baby. This handling stimulates the infants, keeps them alert and assists respiration. Mothers are also urged to come in and breastfeed, and to express breastmilk to facilitate breastfeeding when the baby comes home.

The immediate post-birth period: checking the newborn

Care immediately after birth includes examination of the newborn and placenta for signs of abnormality, weight and length measurements and rating the baby’s wellbeing on the “Apgar scale” at one and five minutes after delivery. The 10 point Apgar scale allots zero to two points each for: heart rate; skin color; muscle tone; reflexes; respiration.

Newborn reflexes checked include:

* The rooting reflex – the turn of a baby’s head when its cheek is touched – nature’s way of ensuring that newborns turn to the nipple right after birth.

* The grasp reflex – newborns hang on to an adult finger so tightly that they can often be pulled upright.

* The “doll’s eye” reflex – eyes pointing in a fixed direction as the head turns.

* The startle or “Moro” reflex – dipping of the head and stretching, then flexing of arms and legs (as if surprised).

* The stepping reflex – a one-day-old infant will “step out” as if walking when held upright on the examining table (a dramatic reflex that disappears by the time a baby is a few weeks of age).

In Canadian hospitals, silver nitrate drops or more usually etythromycin ointment are routinely put into newborn eyes to forestall possible blindness due to maternal gonorrhea. Vitamin K, essential to blood-clotting, is administered to newborns to reduce the risks of hemorragic newborn disease or bleeding. A lack of this vitamin has been linked to potentially fatal hemorrhagic disease of the newborn – at two to five days after birth – before immature livers produce enough vitamin K.

Newborn parent-child bonding

Newborn parent-child bonding, a concept formulated about 20 years ago, refers to communication between parents and newborn within the first minutes and hours of birth. Normal, full-term newborns have a period of “quiet alertness” when, with eyes open, they stare at faces and scan their surroundings. After this initial alert time, newborns usually doze off into a long, deep sleep. To promote parent-child contact in the post-birth moments many maternity units encourage parents to spend time alone with their newborn. However, experts warn that immediate post-birth contact is not “instant glue” and those who miss it have not irrevocably blighted the parent-child relationship!

Rooming-in is now much encouraged. Studies of babies who remain in their mother’s rooms rather than returning to the nursery between feedings show that mothers who keep their newborns rooming-in exhibit greater maternal behavior – more cuddling and feeding – than parents of babies in a central nursery. But if a mother doesn’t want to keep the baby in her room she should not feel “unmotherly” about needing rest.

Breech babies

As birth begins, most full-term babies present head down – in the vertex position with the largest part of the baby, its head, pushing down and dilating the cervix enough to let through the rest of the body. But about three per cent of babies present in a breech position where the baby’s bottom and/or feet press down first, and may not dilate the cervix enough to allow the head through, creating a possible emergency that calls for Cesarean delivery.

Breech babies may present as:

* a frank breech, with the buttocks presenting first and fetal heels up around the ears, the easiest breech position to manage by vaginal delivery;

* a complete breech, where both buttocks and feet present first with foot sole s showing, riskier but still possibly manageable by vaginal birth;

* a footling breech, where the feet appear first, a position rare at term but common with premature babies, which demands a Cesarean section.

The recent Canadian Consensus Report advocates vaginal delivery for frank or complete breech babies provided they have an estimated birth weight of 2,500 to 4,000 grams (five to nine pounds), and that the pelvis is considered “adequate for the after-coming” – for emergence of the baby’s head.

COPYRIGHT 1993 Strategic Inc. Communications Ltd.

COPYRIGHT 2004 Gale Group