Obstetrics

Labour has three stages:

1. The first stage is when the neck of the womb (cervix) opens to 10cm dilated.
2. The second stage is when the baby moves down through the vagina and is born.
3. The third stage is when the placenta (afterbirth) is delivered.
The first stage of labor: dilation
Before labor starts, your cervix is long and firm. During the first hours of labor, the muscles of the uterus (womb) contract and help shorten and soften the cervix, so that it can dilate (open).
For first-time mothers, this stage can last from six to 36 hours. During this time you might experience:
Contractions – some can be quite mild, like a period pain; others can be sharp and strong. Initially, the contractions will be short (between 30 to 40 seconds) and irregular. Once contractions are five minutes apart and a minute or more in length, labor is said to be ‘established’.
A ‘show’ – the discharge of a plug of mucus that can be thick and stringy or blood-tinged. This may happen the day you go into labor, or up to a week before.
‘Breaking of your waters’ – this means the amniotic sac around your baby has ruptured.
Every labor is different. If you think you could be in labor, the first thing to do is relax and stay calm. The best place for early labor is at home.

When to ring your lead maternity carer (LMC) or our Labour & Birthing Suite (if you are giving birth at Auckland City Hospital):
Your contractions are coming every five minutes, lasting longer than 50 seconds, and have been getting stronger for at least two to three hours.
You have severe or constant abdominal pain with a tight abdomen.
Your water has broken and it is clear or has a tinge of pink. Put on a sanitary pad and check it after an hour. If it is wet, please ring us.
Your water has broken and it is green or brown. Call us immediately – you will be advised to come into the hospital.
If there is a change in the pattern of your baby’s movements.
You notice any vaginal bleeding – bright red vaginal bleeding is not normal.
Things to do and try at the hospital:
Try not to tense up during contractions. Your body is trying to release something, not tighten up.
Find positions that feel comfortable. Walk the corridors slowly, lean on the walls, use the Swiss ball and La-Z-boy chairs. Try to stay off the bed, unless for a short rest.
Water is great for relaxation and coping with contractions. If you don’t have use of a pool, try the shower.
Bring music and a player, if it relaxes or calms you.
Bring an electric oil burner and use your aromatherapy oil.
Continue to take refreshments and drink small amounts frequently.
Phone calls are a distraction from your tasks of giving birth and looking after your new baby. Encourage family and friends to phone one designated person for updates.

The second stage of labor: your baby
The second stage of labor begins when the cervix is fully dilated (open) and the baby’s head moves down out of the uterus and into the vagina (or birth canal). Your job at this stage is to push the baby through the birth canal, so you’ll need focused determination and energy.
The birth of your baby may take 30 minutes to an hour or longer. This second stage could be further extended if you have an epidural.
A small number of women will require assistance with their births, either by forceps or ventouse (vacuum extraction). The obstetrician will choose which is best for your situation.

The third stage of labor: the placenta
The final stage of labor is the delivery of the placenta. There can happen in one of two ways listed below.
Your LMC can help you to decide which approach would be best for you, taking into consideration your health, how your pregnancy has progressed and the type of labor and birth you experience.

1. Physiological management
The physiological third stage means waiting for your placenta to deliver spontaneously with your effort. This may take up to an hour following the birth; while you’re waiting, skin-to-skin with your baby and a first breastfeed will be encouraged.

2. Active management
Active management involves injecting an ecbolic (contracting drug) into your leg as your baby’s shoulders are born. The ecbolic speeds up placental separation and your uterus (womb) contracts down to reduce blood loss and ensure your womb remains contracted.

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1. Postpartum hemorrhage (PPH)
When the third stage of labor is prolonged beyond 20-24 minutes (as opposed to the 30 minutes that was the earlier benchmark), it may be a risk factor for postpartum hemorrhage (PPH) which kills more than 1.25 million women a year.

Even when it doesn’t take maternal life, it causes excessive blood loss (over half a liter of blood) following childbirth in a staggering 14 million cases. Most of this bleeding comes from the placental site, which fails to contract properly.

Typically, natural figure-of-8 muscular fiber loops are present around the blood vessels, so that the torn vessels are quickly closed off after the placenta separates and the uterus contracts. PPH is particularly deadly because two out of every three women who develop PPH had no preceding risk factors before delivery.

PPH may also be associated with the following conditions which are also associated with an abnormal third stage. An anemic mother is at higher risk of PPH because clotting is more difficult and because even a relatively small blood loss may precipitate signs and symptoms of hypovolemia due to the initial lack of blood.

2. Retained placenta

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The retention of part or the whole of the placenta, including the membranes, for over 30 minutes after the delivery of the baby, is called the retained placenta. It has several causes:

Premature closure of the cervix so that the separated placenta is trapped inside the uterine cavity
A full urinary bladder prevents the placenta from passing through the birth canal by its pressure
Retention of a part of the membranes or placenta after placental expulsion
The last three conditions may also lead to uterine atony resulting in PPH because the uterus cannot contract well with the placenta inside it.

3. Atonic or flabby uterus:
In some women, the uterus doesn’t contract strongly enough to separate or expel the placenta completely. As mentioned above, a flabby uterus may be associated with a retained placenta, but also with conditions such as:

Placenta previa or implantation of the placenta in the lower part of the uterus, which means the muscle fibers are weakened by the infiltration of blood vessels and placental tissue between them. This leads to weak contractions after the delivery.
Placental abruption or premature separation of the placenta before the child is born
Multiparity: A woman who has already carried more than five pregnancies can have an atonic uterus and PPH.
Multiple pregnancies: If a woman is carrying twins or higher-order pregnancies, the abdomen and uterus are highly distended. The stretched uterine muscle fibers may be unable to contract properly immediately after delivery and this leads to atony.
Polyhydramnios: This refers to the presence of excessive (over 3L) amniotic fluid inside the uterus, which causes overstretching and subsequent atony of the uterine muscle in many cases
Large fetus: A woman carrying a large baby (weighing 4 kg or more) also has the potential for uterine atony because the muscles are weakened by the overstretching.
Prolonged labor and dehydration: If a woman is in labor for over 12 hours, it is more common to have uterine atony, perhaps because of muscular fatigue, dehydration, and acidosis.

4. Uterine inversion
This is a rare but very serious complication of the third stage, slightly more common with controlled cord traction, in which the uterus is turned inside out and comes out through the vulval orifice wholly or partly.

To avoid this, a non-separated placenta should never be pulled out using this technique. Fundal support is also taught as a method of preventing uterine inversion, but not enough evidence exists as to its usefulness. Risk factors for uterine inversion include:

Multiparity
Prolonged labor over 24 hours in duration
Short umbilical cord
Over-zealous cord traction
Use of magnesium sulfate which relaxes muscles, during labor
The placenta accrete when the placenta is firmly attached to the uterine muscle and cannot separate
Congenital uterine anomalies

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