Related Research Articles
Intrauterine growth restriction (IUGR), or fetal growth restriction, refers to poor growth of a fetus while in the womb during pregnancy. IUGR is defined by clinical features of malnutrition and evidence of reduced growth regardless of an infant's birth weight percentile. The causes of IUGR are broad and may involve maternal, fetal, or placental complications.
Preterm birth, also known as premature birth, is the birth of a baby at fewer than 37 weeks gestational age, as opposed to full-term delivery at approximately 40 weeks. Extreme preterm is less than 28 weeks, very early preterm birth is between 28 and 32 weeks, early preterm birth occurs between 32 and 34 weeks, late preterm birth is between 34 and 36 weeks' gestation. These babies are also known as premature babies or colloquially preemies or premmies. Symptoms of preterm labor include uterine contractions which occur more often than every ten minutes and/or the leaking of fluid from the vagina before 37 weeks. Premature infants are at greater risk for cerebral palsy, delays in development, hearing problems and problems with their vision. The earlier a baby is born, the greater these risks will be.
Tocolytics are medications used to suppress premature labor. Preterm birth accounts for 70% of neonatal deaths. Therefore, tocolytic therapy is provided when delivery would result in premature birth, postponing delivery long enough for the administration of glucocorticoids, which accelerate fetal lung maturity but may require one to two days to take effect.
In obstetrics, gestational age is a measure of the age of a pregnancy taken from the beginning of the woman's last menstrual period (LMP), or the corresponding age of the gestation as estimated by a more accurate method, if available. Such methods include adding 14 days to a known duration since fertilization, or by obstetric ultrasonography. The popularity of using this measure of pregnancy is largely due to convenience: menstruation is usually noticed, while there is generally no convenient way to discern when fertilization or implantation occurred.
Pregnancy is the time during which one or more offspring develops (gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins.
Low birth weight (LBW) is defined by the World Health Organization as a birth weight of an infant of 2,499 g or less, regardless of gestational age. Infants born with LBW have added health risks which require close management, often in a neonatal intensive care unit (NICU). They are also at increased risk for long-term health conditions which require follow-up over time.
Prelabor rupture of membranes (PROM), previously known as premature rupture of membranes, is breakage of the amniotic sac before the onset of labor. Women usually experience a painless gush or a steady leakage of fluid from the vagina. Complications in the baby may include premature birth, cord compression, and infection. Complications in the mother may include placental abruption and postpartum endometritis.
Complications of pregnancy are health problems that are related to, or arise during pregnancy. Complications that occur primarily during childbirth are termed obstetric labor complications, and problems that occur primarily after childbirth are termed puerperal disorders. While some complications improve or are fully resolved after pregnancy, some may lead to lasting effects, morbidity, or in the most severe cases, maternal or fetal mortality.
Cervical cerclage, also known as a cervical stitch, is a treatment for cervical weakness, when the cervix starts to shorten and open too early during a pregnancy causing either a late miscarriage or preterm birth. In women with a prior spontaneous preterm birth and who are pregnant with one baby, and have shortening of the cervical length less than 25 mm, a cerclage prevents a preterm birth and reduces death and illness in the baby.
Antenatal steroids, also known as antenatal corticosteroids, are medications administered to pregnant women expecting a preterm birth. When administered, these steroids accelerate the maturation of the fetus' lungs, which reduces the likelihood of infant respiratory distress syndrome and infant mortality. The effectiveness of this corticosteroid treatment on humans was first demonstrated in 1972 by Sir Graham Liggins and Ross Howie, during a randomized control trial using betamethasone.
Cervical weakness, also called cervical incompetence or cervical insufficiency, is a medical condition of pregnancy in which the cervix begins to dilate (widen) and efface (thin) before the pregnancy has reached term. Definitions of cervical weakness vary, but one that is frequently used is the inability of the uterine cervix to retain a pregnancy in the absence of the signs and symptoms of clinical contractions, or labor, or both in the second trimester. Cervical weakness may cause miscarriage or preterm birth during the second and third trimesters. It has been estimated that cervical insufficiency complicates about 1% of pregnancies, and that it is a cause in about 8% of women with second trimester recurrent miscarriages.
Circumvallate placenta is a rare condition affecting about 1-2% of pregnancies, in which the amnion and chorion fetal membranes essentially "double back" on the fetal side around the edges of the placenta. After delivery, a circumvallate placenta has a thick ring of membranes on its fetal surface. Circumvallate placenta is a placental morphological abnormality associated with increased fetal morbidity and mortality due to the restricted availability of nutrients and oxygen to the developing fetus.
A high-risk pregnancy is one where the mother or the fetus has an increased risk of adverse outcomes compared to uncomplicated pregnancies. No concrete guidelines currently exist for distinguishing “high-risk” pregnancies from “low-risk” pregnancies; however, there are certain studied conditions that have been shown to put the mother or fetus at a higher risk of poor outcomes. These conditions can be classified into three main categories: health problems in the mother that occur before she becomes pregnant, health problems in the mother that occur during pregnancy, and certain health conditions with the fetus.
A pre-existing disease in pregnancy is a disease that is not directly caused by the pregnancy, in contrast to various complications of pregnancy, but which may become worse or be a potential risk to the pregnancy. A major component of this risk can result from necessary use of drugs in pregnancy to manage the disease.
Late preterm infants are infants born at a gestational age between 34+0⁄7 weeks and 36+6⁄7 weeks. They have higher morbidity and mortality rates than term infants due to their relative physiologic and metabolic immaturity, even though they are often the size and weight of some term infants. "Late preterm" has replaced "near term" to describe this group of infants, since near term incorrectly implies that these infants are "almost term" and only require routine neonatal care.
The vaginal flora in pregnancy, or vaginal microbiota in pregnancy, is different from the vaginal flora before sexual maturity, during reproductive years, and after menopause. A description of the vaginal flora of pregnant women who are immunocompromised is not covered in this article. The composition of the vaginal flora significantly differs in pregnancy. Bacteria or viruses that are infectious most often have no symptoms.
The placental microbiome is the nonpathogenic, commensal bacteria claimed to be present in a healthy human placenta and is distinct from bacteria that cause infection and preterm birth in chorioamnionitis. Until recently, the healthy placenta was considered to be a sterile organ but now genera and species have been identified that reside in the basal layer.
The uterine microbiome is the commensal, nonpathogenic, bacteria, viruses, yeasts/fungi present in a healthy uterus, amniotic fluid and endometrium and the specific environment which they inhabit. It has been only recently confirmed that the uterus and its tissues are not sterile. Due to improved 16S rRNA gene sequencing techniques, detection of bacteria that are present in low numbers is possible. Using this procedure that allows the detection of bacteria that cannot be cultured outside the body, studies of microbiota present in the uterus are expected to increase.
Sarah K. England is a physiologist and biophysicist and the Alan A. and Edith L. Wolff Professor of Obstetrics and Gynaecology at Washington University School of Medicine. England conducts research on cation channels in uterine smooth muscle to understand the biological correlates of preterm birth and is the Associate Program Director of the Prematurity Research Center at Washington University as well as the Vice Chair of Research for the Center for Reproductive Health Sciences. In 2005, England was selected as a Robert Wood Johnson Foundation Health Policy Fellow in the Office of Senator Hillary Clinton where she used her scientific expertise in obstetrics and gynaecology to guide policy changes.
Lucilla Poston is a physiologist specialising in problems during pregnancy. She is a professor of maternal and fetal health at King's College London.
References
- 1 2 3 4 5 "Professor Rachel Tribe PhD, FPhysiol, FRSB". King's College London. Retrieved 26 May 2021.
- ↑ Tribe, Rachel M; Borin, Mikhail L.; Blaustein, Mordecai P. (1994). "Functionally and spatially distinct Ca2+ stores are revealed in cultured vascular smooth muscle cells". Proc. Natl. Acad. Sci. USA. 91 (13): 5908–5912. Bibcode:1994PNAS...91.5908T. doi: 10.1073/pnas.91.13.5908 . PMID 8016087.
- ↑ "Developing a new test to identify women at risk of premature birth". Borne - research to prevent premature birth. Retrieved 27 May 2021.
- ↑ "PRECISE - PREgnancy Care Integrating Translational Science, Everywhere". PRECISE. Retrieved 27 May 2021.
- ↑ "EQUIPTT – testing an app to calculate risk of premature birth". Tommys. Retrieved 28 May 2021.
- ↑ Carlisle, N; Watson, H A; Seed, P T; Carter, J; Kuhrt, K; Tribe, R M; Shennan, A H (2021). "Impact of a medical mobile phone app (QUiPP) for predicting preterm birth on the anxiety and decisional conflicts faced by women in threatened preterm labour". Midwifery. 92 (92): 102864. doi:10.1016/j.midw.2020.102864. PMID 33137547. S2CID 226241747.
