Are you at risk for preterm birth and wondering how to prevent it?
Have you given birth to a preemie in the past and wondering what you can do in your pregnancy, or future pregnancies to prevent giving birth early again?
Most moms-to-be eagerly await the birth of their babies. Most women at risk of preterm labor and birth, however, want to do anything they can to avoid meeting their new baby too soon.
What is preterm birth?
A full term pregnancy means a pregnancy that has reached 37 completed weeks gestation.
Therefore, according to the World Heath Organization (WHO), preterm birth is defined as any live baby born before 37 completed weeks of pregnancy.
There are three subcategories for premature babies:
- Extremely preterm: under 28 weeks
- Very preterm: 28-32 weeks
- Moderate to late preterm: 32-37 weeks
It’s important to recognize that premature labor does not always lead to premature birth. Sometimes, spontaneous preterm birth can be avoided by attempts to stop or ‘pause’ the process of labor for as long as possible, with medical intervention.
Is preterm birth the same as premature birth?
You might have heard the term ‘premature’ birth, and wondered whether there is a difference between that, and the term ‘preterm’ birth.
Both terms mean the same thing, but different cultures or countries might favor one term over the other.
You health care provider might also prefer to use one rather than the other.
Both terms refer to babies born prematurely, before 37 completed weeks gestation.
Why is prevention of preterm birth important?
Premature birth facts
Many of us are aware that it’s generally not ideal for babies to be born too early, but do we really know why, or what impact premature birth might have?
You might be wondering why preventing early labor and birth really matters.
Here are some of the facts:
- The WHO estimates that 15 million babies are born too early each year, globally
- This figure means approximately 1 in 10 (10%) babies are born prematurely
- Preterm birth complications are the leading cause of death in children under 5
- Rates of preterm birth are on the rise, globally, partly due to raised maternal age and the increased use of assisted reproductive technology (including in vitro fertilization).
According to research, premature birth and associated complications account for around 1 million deaths per year, globally.
In recent decades, medical technology has come a long way with regard to premature baby care. Survival rates for even the smallest of babies has improved dramatically.
This is due to a number of reasons, including: the use of antenatal steroids in pregnancy, improved neonatal resuscitation, improved NICU care, and preventative efforts to reduce preterm labor.
Due to improved care, about 40-70% of babies born at 24 weeks gestation will survive. By 32 weeks, survival rates rise to 98% for babies born prematurely.
However, inequalities in survival rates differ hugely around the world, with major differences in survival rates between low and high income countries.
For example, more than 90% of extremely preterm babies (less than 28 weeks) born in low-income countries die within the first few days of life; in high-income settings, less than 10% of extremely preterm babies die.
What are the risks of preterm birth on the baby’s health?
For babies, surviving premature birth is only the first hurdle.
An early birth puts babies at an increased risk of many short and long term health concerns.
Although technology can save many premature babies, being born early increases their risk of physical, developmental, and neurological disabilities. In simple terms, being born too early can significantly affect your baby’s health.
Premature babies are at an increased risk of:
- Being admitted to a neonatal intensive care unit (NICU) – sometimes also referred to as a SCBU (special care baby unit) or NNU (neonatal unit)
- Serious breathing problems – often requiring a ventilator machine to support their breathing (life support)
- Serious infection
- Bleeding on the brain
- Cerebral palsy
- Developmental delays
- Poor weight gain/weight loss
- Feeding problems
- Physical disabilities
- Visual and/or hearing impairment
- Behavioral and social-emotional problems
- Increased risk of ADHD (attention deficit hyperactivity disorder)
- Sudden infant death syndrome (SIDS)
- Death (within the first 28 days of life).
Read more about this in SIDS And Safe Sleep – How Safe Is Your Baby?
Interestingly, babies who are born prematurely are also more likely, as adults, to develop certain chronic diseases such as diabetes, heart disease, and hypertension (high blood pressure).
It’s safe to say that prematurity carries additional health risks, stresses, and challenges for babies born early, not just in the immediate short term and neonatal period, but also into adulthood.
I gave birth to a 31-week baby a couple of years ago. She had an uneventful NICU stay, came home exclusively breastfeeding, and was in good health overall.
Since her birth, however, she has had plenty of physical and occupational therapy. This is to address the physical challenges she faces as a result of being born prematurely.
She has an excellent prognosis and is doing amazingly well. However, if she’d been able to stay in utero at least 6 extra weeks, she wouldn’t need therapy to meet physical milestones.
How early can preterm labor start?
Preterm labor occurs when regular contractions cause the cervix to begin opening earlier than normal. This can happen at any time between 20 and 37 weeks.
The earlier a baby is born, the greater the health risks for the baby.
Contact your health care provider immediately if you have any of the following symptoms before 37 weeks:
- Regular contractions or tightenings
- Period type pains
- Vaginal bleeding, or a gush or trickle of fluid (this could be amniotic fluid)
- Unusual back ache
- Signs of infection.
Find out more in our article What’s The Earliest A Baby Can Be Born And Survive?
What triggers preterm labor?
We’re not absolutely certain why some babies are born early following spontaneous labor.
Most preterm births occur spontaneously, due to early onset of labor, an infection, or if the amniotic fluid around the baby breaks too early.
Some premature births are due to early induction or C-Section Birth, whether for medical or non-medical reasons.
Around 20% of preterm births are iatrogenic, which means they are caused by medical intervention. For example, in the occurrence of certain severe fetal or maternal conditions, it might be safer for the baby to be born early, considering the increasing danger of various medical conditions such as Preeclampsia, Placental Abruption or fetal growth restriction.
We know there are certain risk factors for preterm labor; a large proportion of preterm births, however, happen without any risk factors or known causes.
Risk factor screening alone will fail to identify more than 50% of pregnancies that will birth preterm.
Risk factors for preterm birth
- Age. Women younger than 18 and older than 30 years are most at risk of preterm birth. Teenage moms are more likely to have blood pressure problems in pregnancy and older moms are more likely to have underlying health conditions prior to pregnancy
- Ethnicity. It isn’t clear why, but black women are more likely to have premature babies than white and hispanic women
- Previous preterm birth. This is the biggest risk factor for preterm labor and birth
- Multiple pregnancies. Carrying more than one baby increases your chances of early labor. More than half of all twins are born early
- Maternal smoking. One of the biggest risks of smoking in pregnancy is the increased chance of preterm birth
- Alcohol intake. There’s no safe amount of alcohol to consume in pregnancy. If you drink alcohol in pregnancy you increase your risk of preterm birth
- Recreational or street drugs. The use of non-prescription drugs increases your risk of preterm birth and can cause harm to you and your baby
- Poor nutrition. Being over or under weight can result in pregnancy complications, including preterm birth
- Chronic high blood pressure. Significantly high blood pressure before pregnancy increases your odds of BP problems, such as pre-eclampsia in pregnancy. Pre-eclampsia needs close monitoring and often requires medication to control blood pressure. Sometimes medication alone is not enough to reduce blood pressure to a safe level, leaving no option but to deliver the baby early
- Diabetes. Women with pre-existing diabetes are at increased risk of various pregnancy complications, including polyhydramnios (Too Much Amniotic Fluid) which increases the risk of preterm birth
- Untreated infection. Infections left untreated, particularly urinary tract and uterine infections, can lead to preterm birth
- Lack of prenatal care. Late access to prenatal care, or a lack of health care altogether, can lead to late diagnosis of serious pregnancy complications or inadequate treatment, increasing the likelihood of early labor.
Read this article What Are The Effects Of Smoking While Pregnant? Risks And Facts for important information.
Preterm birth – ways to prevent preterm birth
The best way to avoid preterm birth is to strive for a healthy pregnancy and to try to prevent preterm labor from occurring in the first place.
Women with a higher risk of going in to preterm labor, can be supported by their health care provider in a preterm birth prevention clinic. They will be provided specialist care, probably with involvement of their midwife and obstetrician.
It’s unclear why some women go into preterm labor and others don’t; as a result, it’s difficult to figure out which interventions work best to reduce or prevent it.
A New Blood Test Predicting Premature Birth with 86% Accuracy has been developed to help predict women at risk of preterm labor early.
How to prevent preterm birth in pregnancy
Below are some common interventions which might be suggested by your health care provider.
A recent review of the research into interventions that could help reduce preterm birth or prevent the death of a baby (perinatal death), found the following had clear benefits in reducing preterm birth for specific women:
- Midwifery-led continuity models of care as opposed to other models of care
- Screening pregnant women for lower genital tract infections (UTIs, STIs, etc.) and treating them, as needed. Untreated infection creates an increased risk for preterm birth; however, some minor infections can go unnoticed by a pregnant woman
- Zinc supplementation, for women without systematic illness
- A cervical stitch (cerclage) for women at high risk of preterm birth, and pregnant with only one baby.
In addition, the following showed possible benefits in reducing preterm birth in some groups of women:
- Group antenatal care (prenatal visits) for all pregnant women
- Antibiotic treatment for urinary tract infections with no obvious symptoms (asymptomatic bacteriuria)
- Pharmacological interventions for smoking cessation
- Vitamin D supplements alone for women without health problems.
It’s equally important to note the review did not find any interventions to reduce preterm labor with clear known risk.
However, they did find a few things that have potential risks. They include:
- Intramuscular progesterone injections, for women at higher risk of preterm birth while pregnant with multiples
- Taking vitamin D supplements, calcium or other minerals, where there were no health problems or deficiencies.
Let’s discuss some common interventions in more detail:
Transvaginal ultrasound for measuring cervical length
For pregnant women at an increased risk of preterm labor and birth, it’s considered routine to monitor the cervix regularly for a change in length, using an internal vaginal (transvaginal or TV) ultrasound.
A short cervix is defined as a cervical length less than 20mm. A pregnant women with a cervical length less than 20mm has a 50% chance of preterm labor.
The theory is that a shortened cervix is more likely to begin opening too early, leading to premature birth.
This form of monitoring is sometimes referred to as cervical surveillance.
Cervical measurements should begin from 19-24+6 weeks gestation, and are often performed at the same time as a routine anatomy (mid-trimester) scan.
If the cervical length is below the 10th centile for gestational age in the second trimester, preterm labor before 35 weeks is 6 times more likely.
Progesterone for preterm birth prevention
You might have already heard about, or know someone who has used, progesterone supplementation to prevent her from giving birth early.
You might be wondering whether this form of preventative treatment is effective.
In 2011 the FDA (Food & Drug Administration) approved the use of progesterone supplementation in pregnancy to reduce the risk of recurrent preterm labor and birth, in women with a singleton pregnancy (1 baby) and with at least one previous preterm birth.
The National Institute of Clinical Excellence (NICE) in the UK, the International Federation of Gynaecology & Obstetrics (FIGO), and the Society for Maternal-Fetal Medicine (SMFM) in the USA, all recommend the use of progesterone for women at high risk of preterm labor and birth.
Both NICE and FIGO recommend the use of vaginal progesterone (gel, suppository, or cervical pessary), whereas SMFM recommends intramuscular (IM) progesterone injections.
It is intended for daily use from 16-20 weeks up to 37 weeks gestation.
Progesterone therapy is not suitable for you if:
- You’re carrying more than one baby
- Your waters have already broken (premature rupture of membranes)
- You’ve had a positive fetal fibronectin (fFN) test (a test to rule out preterm labor)
- You’ve had a previous episode of preterm labor which was successfully stopped.
It’s important to recognize that progesterone therapy might not always be successful in preventing preterm birth.
What does the research say?
Studies show that progesterone was the only consistent intervention that appeared to reduce the risk of preterm birth and neonatal death; however, less benefit was noted in the better quality trials.
The findings suggested that for women at risk of preterm birth, progesterone in any form could reduce preterm birth before 34 weeks by up to 55%.
However, these findings were contrary to the results of recent large UK based trials, which found less benefit.
Further research and better quality trials are required. Therefore the jury is still out as to how effective progesterone is in reducing preterm birth.
NICE is currently revising its guidelines in the UK. However, it currently recommends a choice of either vaginal progesterone (PV) or a cervical cerclage (stitch) should be offered to all women with both a previous preterm birth and a cervical length of less than 25mm on ultrasound between 16-24 weeks.
For women who have a short cervix but no previous preterm birth, PV progesterone should be offered.
How does progesterone prevent preterm birth?
Progesterone is an essential hormone for reproduction.
Progesterone is initially produced by the corpus luteum until around 8 weeks, when the placenta takes over production.
In early pregnancy, progesterone prepares the uterus and is responsible for maintaining the pregnancy.
Levels rise steadily throughout the pregnancy until the onset of labor. Progesterone inhibits oxytocin and therefore contractions, protecting the baby from preterm labor.
At the onset of labor, progesterone levels decrease, enabling oxytocin levels to rise and allowing spontaneous physiological labor to occur.
Fetal fibronectin testing
Fetal fibronectin (fFN) is a protein believed to help keep the amniotic membranes ‘glued’ to the wall of the uterus. If it becomes disturbed, the protein can be released into vaginal discharge or secretions near the cervix.
If you’re experiencing signs or symptoms of preterm labor (between 22 and 34 weeks), your health care provider might suggest doing a fFN test. This is performed with a simple vaginal swab, which can detect the presence of this protein.
If the test is positive, you’re at an increased risk of preterm labor within 7 days.
The test can provide valuable information in care planning. You might be offered steroid injections to help mature your baby’s lungs in preparation for an early birth.
How to prevent preterm birth in second pregnancy
If you’ve already had a premature baby, you might have concerns about what will happen next time around. Or maybe you’re currently pregnant and wondering what are the chances of it happening again.
This can be a big concern for many parents and, in some cases, the thought of it can prevent them from considering trying for another baby.
If this is you, the figures below show the risk of spontaneous preterm birth, following one or more preterm births.
- 1 previous preterm birth = 15% chance of having another preterm birth
- 2 previous preterm births = 40% chance of having another preterm birth
- 3 previous preterm births = 70% chance of having another preterm birth.
We know that the biggest risk factors for preterm birth are a previous preterm birth and a shortening or short cervix.
Although this can be worrying, knowing your chances ahead of time will help you to make the most appropriate choices for you when it comes to planning your family.
How does midwifery care reduce preterm birth?
If you’re familiar with BellyBelly content, you know we mention midwifery care quite often.
Of course you also know we value evidence-based information.
Above all, we write about and encourage midwifery care because we value evidence-based information.
As you have read, research has shown a clear benefit in using midwifery care.
As well as this, a WHO report found midwives provide care that is equal to and, in some cases, better than care provided by physicians.
Be sure to read Midwives And Nurses Can Provide Equal Or Better Care Than Physicians – WHO Report to learn more.
The research talks about a midwifery style known as continuity of care.
It isn’t that physicians aren’t able to, or don’t, provide exceptional care; it’s simply that most midwifery models of care offer greater continuity.
A known midwife becomes familiar with you and your unique pregnancy. Midwifery models of care notice warning signs of possible complications, such as preterm birth, early on.
In addition, lifestyle, Pregnancy Nutrition, prenatal care, and other things can reduce the risk of preterm birth.
The midwifery model of care also educates women about nutrition and wellness during pregnancy.
Healthy pregnancy lifestyle
As we know, there are some elements of pregnancy and birth that are out of our hands.
However, there are many simple things that you can do in order to have as healthy a pregnancy as you can, and also to minimize your chances of preterm birth.
Here are some pregnancy lifestyle basics to keep in mind:
Prior to pregnancy:
- Reduce or stop your alcohol intake. Drinking Alcohol While Pregnant in any amount increases your risk of preterm labor, birth defects, and fetal alcohol spectrum disorders
- Quit smoking. Women who quit smoking in early pregnancy, reduce their risk of adverse effects, such as preterm birth, stillbirth, small for gestational age, and low birth weight, to rates very similar to those of non-smokers
- Quit use of non-prescription drugs. Recreational drugs, such as marijuana (cannabis), ecstasy, cocaine, or heroin, can harm you and your baby during pregnancy and put you at an increased risk of premature birth
- Maintain a healthy weight. Excessive Pregnancy Weight Increases Birth Defects and is associated with many other adverse health complications. Obesity is therefore attributed to medically indicated preterm births. On the other end of the scale, an extremely low body mass index (BMI) in early pregnancy is also consistently reported as a risk for preterm birth, compared with those of a healthy weight
- Eat a balanced diet. Your diet should also include foods rich in folic acid, iron, and zinc, but do not eat raw meat
- Reduce Stress During Pregnancy. There are links between maternal stress and preterm birth
- Stay active. Aim for at least 30 mins of daily exercise
- Pre-pregnancy support. Get any medical conditions, such as diabetes, raised blood pressure, or autoimmune disease, under control.
Continue to do all of the above, or begin working on them now that you’re pregnant.
- Seek prenatal care early, particularly if you have any medical conditions, or if you’re at risk of preterm birth
- Report any signs of preterm labor.
Are you at risk for preterm labor? Be sure to read Premature Labour – Signs, Symptoms and Management to learn more.
To learn more about premature birth, be sure to read: