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Preterm Labor

Premature Labor


The following signs and symptoms confirms the occurrence of preterm labor:

  • Spotting or early bleeding due to the early effacement of the cervix.
  • Progressive and frequent uterine contractions. usually 5 or more contractions per hour.
  • Low back pain secondary to the impinging head of the baby in the birth canal.
  • Fluid leak or gush primarily due to the premature rupture of membranes.
  • Bloody mucous discharge suggests that the cervix is starting to open.
  • Recognition of the early signs of pulmonary edema enable swift clinical diagnosis and steps to be taken to prevent disasterous condition due to progressive hypoxemia.[ncbi.nlm.nih.gov]
  • Physical examination disclosed wet rales over both lungs, sinus tachycardia and tachypnea.[ncbi.nlm.nih.gov]
  • The diagnosis of pulmonary edema was confirmed by abnormal findings in the chest roentgenogram, bilateral rales, and a decrease in arterial blood oxygen pressure.[ncbi.nlm.nih.gov]
Wet Rales
  • Physical examination disclosed wet rales over both lungs, sinus tachycardia and tachypnea.[ncbi.nlm.nih.gov]
Abdominal Pain
  • METHODS: Prospectively collected data of pregnant women presenting with symptoms of preterm labor (abdominal pain or tightening) at 24-34 weeks' gestation were retrieved from the research databases of the EQUIPP and PETRA studies for subanalysis.[ncbi.nlm.nih.gov]
  • Signs and symptoms include abdominal pain, menstrual-like cramping, low back pain, and vaginal spotting or bleeding. DISCHARGE INSTRUCTIONS: Call 911 for any of the following: You see or feel like there is something in your vagina.[drugs.com]
  • Wellbeing of Women ELS Jane Currie (A David primary supervisor) “Do women presenting with abdominal pain and negative urine dipstick tests in pregnancy have subclinical urinary tract infection?”[ucl.ac.uk]
  • pain, menstrual-like cramping, or more than four contractions in one hour (even if they don't hurt) More pressure in the pelvic area (a feeling that your baby is pushing down) Low back pain, especially if it's dull or rhythmic, or you didn't previously[babycenter.com]
Epigastric Pain
  • Hypertension and epigastric pain could not be controlled after the operation.[ncbi.nlm.nih.gov]
  • A patient we recently treated for preterm labor learned to recognize contractions by the associated symptoms of autonomic hyper-reflexia: flushing, headache, and piloerection.[ncbi.nlm.nih.gov]
Back Pain
  • Lower backache If you’re nearing the home stretch of your pregnancy, back pain may be all too familiar.[monbaby.com]
  • The signs of premature labor include regular contractions that increase in intensity, back pain, pressure in your vagina, vaginal discharge or bleeding, and decreased fetal movement.[livestrong.com]
  • Other benefits of exercising while pregnant include: 34 percent reduction in back pain when women randomize exercise throughout pregnancy Possible risk reduction of pregnancy complications like gestational diabetes and preeclampsia In short, exercising[healthcare.utah.edu]
  • If you have any symptoms of preterm labor, including contractions, cramps, back pain, or leaking of fluid from your vagina, contact your healthcare provider right away.[urmc.rochester.edu]
Vaginal Discharge
  • The results of vaginal discharge tests and maternal serum C-reactive protein (CRP) level at admission, placental biopsy, and perinatal outcomes were searched. The prevalence of abnormal vaginal flora was calculated.[ncbi.nlm.nih.gov]
  • If you have any of these signs or symptoms before 37 weeks of pregnancy, you may be having preterm labor : Change in your vaginal discharge (watery, mucus or bloody ) or more vaginal discharge than usual Pressure in your pelvis or lower belly, like your[marchofdimes.org]
  • This mother holds her premature baby skin to skin as he receives food through a tube Call Your Healthcare Provider Preterm labor warning signs: Change or increase in vaginal discharge (watery, mucus-like, or bloody) Pelvic or lower abdominal pressure[ubeclass.injoyonlineeducation.com]
Pelvic Pain
  • If you are entering labor, you may notice symptoms such as a heavy feeling in the pelvis, cramping, spotting or bleeding, backache, and intermittent pelvic pain that lasts 30 to 90 seconds.[nyulangone.org]
  • Vaginal bleeding Vaginal discharge that is unusual Severe, persistent, frequent headaches Pain or burning upon urination, or decrease in urination Persistent nausea or vomiting Leakage of fluid from the vagina Sharp pelvic pain or severe cramping Frequent[sidelines.org]
  • Keep in mind that you can have some or all of these symptoms and not be in labor (most pregnant women experience pelvic pain/pressure or lower back pain at some point). But only your practitioner can tell for sure, so pick up the phone and call.[whattoexpect.com]
Regular Uterine Contractions
  • This communication describes a case of a pregnant woman who had an allergic reaction and regular uterine contractions after the ingestion of lobster meat, to which she was known to be allergic.[ncbi.nlm.nih.gov]
  • Definition Preterm labor : Regular uterine contractions with cervical effacement , dilation, or both before 37 weeks gestation.[amboss.com]
  • uterine contractions occur at least 1 time in 10 minutes and persist for more than 30 minutes before completion of 37 weeks of gestation without dilatation of the cervix.[dovepress.com]
  • The effective dose was maintained for at least six hours after the cessation of regular uterine contractions; the dose was then progressively decreased until the infusion was ended.[nejm.org]
  • Signs and Symptoms of Preterm Labor Regular uterine contractions or tightening sensation in stomach (often painless) Continuous or intermittent menstrual-like cramps (constant or occasional) Low, dull backache Pelvic pressure Abdominal cramping, with[sidelines.org]
Vulvar Edema
  • With no further treatment, the vulvar edema gradually resolved during the next week.[ncbi.nlm.nih.gov]


The diagnosis of preterm labor precludes with the accurate determination of fetal gestational age that falls beyond 20 weeks and lower than 37 weeks, with concurrent regular contractions and vaginal spotting.

The following tests and procedures may be utilized to help in the diagnosis of preterm labor:

  • Pelvic Examination will give the obstetrician an idea of how the baby may present during delivery, estimate the firmness of the uterus, and determine whether the cervix has started to open.
  • Ultrasound: A pelvic sonogram can determine the accurate age of the fetus, its relative presentation, amniotic fluid volume, length of cervix and baby’s size.
  • Uterine monitor will determine the actual spacing of the uterine contractions.
  • Fetal monitoring is used to monitor the fetal heart rate during the course of the labor to determine the child’s well-being.
  • Laboratory test: Vaginal swabs may be taken to determine the presence of fibronectin and the possible presence of infectious organisms. 
  • Maturity amniocentesis: This laboratory study involves the extraction of amniotic fluid when the age of gestation is beyond 32 weeks to determine the fetal lung age and determine the presence of amniotic fluid infections [6].
Pericardial Effusion
  • During treatment, one twin developed closure of the ductus arteriosus, tricuspid regurgitation, right ventricular dysfunction, and pericardial effusion. Severe oligohydramnios in both amniotic sacs appeared as well.[ncbi.nlm.nih.gov]
Listeria Monocytogenes
  • Two cases of Listeria monocytogenes chorioamnionitis in association with preterm labor are presented. The pathogenicity and the recommended treatments of listeriosis in regard to the pregnancy outcomes of our patients are discussed.[ncbi.nlm.nih.gov]


The following treatment modalities are done to prevent the progression of preterm labor to preterm delivery:

  • Cervical cerclage: This surgical procedure is done to reinforce the cervix and prevent preterm birth in an incompetent cervix condition.
  • Corticosteroids: Patients in preterm labor between 24 to 34 weeks of gestation may benefit from betamethasone or dexamethasone injections to hasten the lung maturity of the neonate before preterm birth [7].
  • Tocolytics: This group of medications may be given to patients in preterm labor to halt the uterine contractions and its progression. Tocolytics are not routinely given to preterm labor cases beyond 34 weeks, deliveries are postponed till the 37th weeks to significantly lower neonatal mortality and morbidity [8]. The use of magnesium sulfate as a tocolytic agent has been found to decrease the incidence of cerebral palsy and low birth weight infants [9].


Patients with less frequent contraction without bleeding may still be able to tocolyze the preterm labor till term pregnancy. However, patients presenting with rapid contractions with eminent bleeding may have an increased chance to progress to preterm delivery.

The relative prognosis of neonates born through preterm labor varies directly with age of gestation, and varies inversely with the number of congenital defects seen. This prognostic relationship is also true with maternal and neonatal morbidity and mortality ratings respectively.


The following medical conditions are common complication of preterm labor:

  • Preterm delivery
  • Premature rupture of membranes
  • Premature neonate
  • Neonatal sepsis
  • Recurrent preterm labor


The progression to preterm labor is influenced by the maternal health, lifestyle and inherent anatomical defects. The following etiologic factors may lead to preterm labor:


Preterm labor initiates more than half of preterm deliveries and is considered as the leading cause of neonatal mortality in the United States today [3]. Preterm births accounts for the 70% of neonatal morbidity and mortality [4].

The relative risk of preterm births due to preterm labor may be averted by the prompt and early identification of risk factors among mothers with less than 37 weeks of gestation. The active reduction of extreme prematurity (less than 32 weeks) will significantly reduce the mortality, morbidity and the inherent expenses during the delivery [5].

Sex distribution
Age distribution


The pathophysiology of preterm labor lies on the nature of the inciting factor that induces labor. Preterm infection like chorioamnionitis or maternal septicemia may trigger uterine labor prematurely. The relative mass of the conceptus pressing against the thinning cervix may be influenced by twining or multiple pregnancies. Consequently, the cervical competence and amniotic fluid volume is also an important contributory factor in the progression of the preterm labor.

Extrinsic factors that trigger neurotransmitter release in the maternal system like cigarette smoking, psychological stress and physical stress may induce premature contractions of the uterus.


Mothers who begin to feel uterine contractions should take a short walk, change position or rest for a few minutes to quell the preterm contractions at home. Frequent false contractions in the preterm period is a risk factor for preterm labor in the late preterm stages (34-36 weeks) [10].

Persistent contraction despite these remedies must be brought in to the nearest obstetric care facility for proper assessment and monitoring. Adequate rest and fluid intake during intermittent uterine contractions may prove to be beneficial in some cases of preterm labor.


Preterm labor is a clinical condition defined as the premature opening of the cervix due to frequent uterine contractions before 37 weeks of gestation. When such event is unabated, this may result to the delivery of a premature baby that may require special care upon birth and may be at risk to long term complications. Mothers who underwent preterm labor may be at risk to another preterm labor on her next pregnancy.

Patient Information


Preterm labor is defined as the frequent uterine contraction that lead to the opening of the cervix before term pregnancy.


Multiple pregnancy, infections, stress, cervical incompetence, deficient amniotic fluid, placental abruption, and placenta previa may lead to preterm labor.


Frequent uterine contractions with shorter intervals, bleeding per vagina, cervical effacement and early rupture of membranes are common symptoms.


Pelvic examination, ultrasound, fetal and uterine monitoring and amniocentesis are used to diagnose preterm labor.

Treatment and follow-up

Cervical cerclage, corticosteroids to enhance fetal lung maturity, and tocolytics to control preterm contractions are the treatment options.



  1. Lykke JA, Paidas MJ, Langhoff-Roos J. Recurring complications in second pregnancy.Obstet Gynecol. Jun 2009; 113(6):1217-24.
  2. Durnwald CP, Walker H, Lundy JC, Iams JD. Rates of recurrent preterm birth by obstetrical history and cervical length. Am J Obstet Gynecol. Sep 2005; 193(3 Pt 2):1170-4.
  3. American College of Obstetricians and Gynecologists. ACOG Practice Bulletin. Assessment of risk factors for preterm birth. Clinical management guidelines for obstetrician-gynecologists. Number 31, October 2001. (Replaces Technical Bulletin number 206, June 1995; Committee Opinion number 172, May 1996; Committee Opinion number 187, September 1997; Committee Opinion number 198, February 1998; and Committee Opinion number 251, January 2001). Obstet Gynecol. Oct 2001; 98(4):709-16.
  4. ACOG practice bulletin. Management of preterm labor. Number 43, May 2003. Int J Gynaecol Obstet. Jul 2003; 82(1):127-35.
  5. Eden RD, Penka A, Britt DW, Landsberger EJ, Evans MI. Re-evaluating the role of the MFM specialist: lead, follow, or get out of the way. J Matern Fetal Neonatal Med. Oct 2005; 18(4):253-8.
  6. Romero R, Miranda J, Chaiworapongsa T, et al. A novel molecular microbiologic technique for the rapid diagnosis of microbial invasion of the amniotic cavity and intra-amniotic infection in preterm labor with intact membranes. Am J Reprod Immunol. Apr 2014; 71(4):330-58.
  7. Crowther CA, McKinlay CJ, Middleton P, Harding JE. Repeat doses of prenatal corticosteroids for women at risk of preterm birth for improving neonatal health outcomes. Cochrane Database Syst Rev. Jun 15 2011; 6:CD003935.
  8. Cheng Y, Kaimal A, Bruckner T, Hallaron D, Caughey A. Perinatal morbidity associated with late preterm deliveries compared with deliveries between 37 and 40 weeks of gestation. BJOG. Nov 2011; 118(12):1446-1454.
  9. Conde-Agudelo A, Romero R. Antenatal magnesium sulfate for the prevention of cerebral palsy in preterm infants less than 34 weeks' gestation: a systematic review and metaanalysis. Am J Obstet Gynecol. Jun 2009; 200(6):595-609.
  10. Chao TT, Bloom SL, Mitchell JS, McIntire DD, Leveno KJ. The diagnosis and natural history of false preterm labor. Obstet Gynecol. Dec 2011; 118(6):1301-8.

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Last updated: 2018-06-22 12:00