Premature Babies – Causes, Care & Complications

By (embryologist), (gynecologist) and (fertility counselor).
Last Update: 08/08/2016

Uneventful pregnancies last 40 weeks since the first day after the last menstruation. Therefore, newborns are classified in different groups according to their week of birth:

  • Preterm delivery: to be discussed later on.
  • Full term delivery: a birth that takes place between the weeks 37-42.
  • Post-term delivery: a birth taking place beyond the 42nd week.

What is a preterm birth?

A premature newborn, also known as preemie baby, is a baby who is born before the 37th week of gestation as a result of a delivery that takes place sooner than expected.

This is the case of 8-12% of pregnancies. Once the main causes of infant mortality are considered, nowadays the chances of survival are higher than ever: a fairly solid 80% of preterm newborns survive.

Those that are born between the 35th-37th week would not arguably be labeled as late prematures. It is unlikely that staying in ICU is necessary. Nonetheless, they must be observed in a way full-term newborns do not need.

We can tell a baby is born prematurely if the following features are identified if compared to a full term baby:

  • Big head, low weight (<2.5 kg) and poor muscle mass.
  • Smooth, thin, bright skin being almost traslucid, some veins and arteries are easy to distinguish.
  • Smooth and flexible ear cartilage.
  • Reddened feet and hand palms, poor crease-formation.
  • Presence of lanugo hair.
  • Low body temperature.
  • Breathing problems due to underdeveloped lungs and risk of pulmonary bleeding.
  • Weak weeping.
  • Newborn's jaundice and risk of hypuglucaemia.
  • Weak suction and swallowing.
  • Underdeveloped genitalia: enlarged clitoris in girls and small scrotum in boys.

Signs of preterm labor

There are some symtpms that may warn the mother about a potential premature labor:

  • Having four or more contractions per hour before the 37th week.
  • Loss of amniotic fluid through the vagina. That may be indicating the premature rupture of the membranes that protect the unborn.
  • Feeling pressure in the pelvis or feeling of weight, a possible sign of the baby descending throughout the birth canal.
  • Menstrual cramping, abdominal, or back pain and even vaginal bleeding.

If the mother notices some of the following symptoms, she must go to the hospital immediately.

Preterm delivery complications

A fetus grows the most during the last 8 weeks of gestation. In the first 32 weeks, the baby grows up to a third of the total weight, and during the last 8 weeks, the unborn reaches the 2/3 left. The fetal organs have a similar pattern, being these last 8 weeks essential to achieve a full growth.

Premature newborns can suffer problems in the long term, but it is not possible to make prudent prediction of the clinical evolution of the baby relying only on the gestational age or weight at birth.

Thus, the smaller or underdeveloped the newborn is, the greater the risks are. The respiratory, nervous, digestive, renal, immunologic and visual sistems might be compromised, being the respiratory one of the most affected.

Premature baby care

To establish a set of measures, the newborn has to be assessed immediately. Usually, this kind of babies need to be tube-fed until breastfeed due to their suction and deglutition problems before 34th week. Also, the newborn may require assistance to overcome any respiratory deficiency, although it depends on the stage of prematurity of the newborn.

Therefore, an early baby cannot be taken care of at home, because the newborn needs specialized caring. He/she will have to stay in an incubator, which plays the role of a transitory uterus. It will keep the baby warm an under specific humidity conditions (30 °C, 80-90%).

The premature baby will be released in the moment assisted respiration and the warmth of the incubator are no longer required, being also necessary to have a proper weight and to suckle well.

Preterm birth prevention

In order for a preterm birth to be prevented, and for the baby to be born in due date, prospective mothers are recommended:

  • To be in good health condition prior to getting pregnant.
  • To receive prenatal cares as soon as possible, keeping them until the baby is born.

Sometimes, preterm birth can be treated with a drug that blocks uterine contractions. Such drug is the betamethasone, but most of the times these attempts to delay it turn out to be ineffective.

FAQs from users

Is a preterm birth more likely with twins?

By Manuel Aparicio Caballero M.D., M.Sc. (gynecologist).

According to the World Health Organization (WHO), a preterm birth occurs when the child is born before the week 37 of pregnancy. Some of the most common causes of preterm birth are:

  • Overdistention of the uterus: loss of tone in the uterine musculature that prevents this organ to recover its normal size.
  • Infection or uterine inflammation: certain bacteria can damage fetal membranes by causing its rupture and triggering a preterm birth. An infection that affects the uterus directly may lead to preterm birth as well.
  • Decidual bleeding: a type of vaginal bleeding that may occur while a woman is pregnant.

There exist many risk factors that can lead to premature birth, including obesity, high blood pressure, etc. A multiple pregnancy is one of these factors.

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Authors and contributors

 Cristina Mestre Ferrer
Cristina Mestre Ferrer
B.Sc., M.Sc.
Bachelor's Degree in Biological Sciences, Genetics & Human Reproduction from the University of Valencia (UV). Master's Degree in Biotechnology of Human Assisted Reproduction from the UV and the Valencian Infertility Institute (IVI). Embryologist at IVI Barcelona. More information about Cristina Mestre Ferrer
 Manuel Aparicio Caballero
Manuel Aparicio Caballero
M.D., M.Sc.
Bachelor's Degree in Medicine from the University of Murcia. Specialist in Obstetrics & Gynecology. Master's Degree in Human Reproduction from the King Juan Carlos University and the IVI. Currently, he is part of the team of Tahe Fertilidad (Murcia, Spain). More information about Manuel Aparicio Caballero
License: 303008030
Adapted into english by:
 Sandra Fernández
Sandra Fernández
B.A., M.A.
Fertility Counselor
Bachelor of Arts in Translation and Interpreting (English, Spanish, Catalan, German) from the University of Valencia (UV) and Heriot-Watt University, Riccarton Campus (Edinburgh, UK). Postgraduate Course in Legal Translation from the University of Valencia. Specialist in Medical Translation, with several years of experience in the field of Assisted Reproduction. More information about Sandra Fernández

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