Study of changes in levels of salivary estriol and progesterone in preterm labor in comparison to normal pregnancy

Richa Yadav, Urmila Singh


Background: This prospective research was designed to evaluate changes in levels of salivary Estriol and Progesterone in preterm labor in comparison to normal pregnancy. Spontaneous onset of labor at term is produced by definite increase in estriol and fall in progesterone. This rise in free estrogen should precede the onset of labor according with the known effect of estrogen and progesterone on myometrial activity. Concentration of steroid in saliva reflect unbound unconjugated and biologically active fraction.

Methods: The present study was carried for duration of one year enrolling 115 antenatal women between 28 and < 37 weeks of gestation with or without labour pains attending the antenatal clinic in KGMU, Lucknow and those admitted in Queen Mary’s Hospital Lucknow. 5 ml of saliva was collected in cryovials from each patient to estimate estriol and progesterone. The estimation of saliva progesterone and estriol was done by immunoenzymatic colorimetric method of the supernatant of sample.

Results: In our study mean value of saliva progesterone levels of pregnant women with preterm delivery (study group IIA) was lower than the control group (Group l) but the difference was not significant (3814.46±751.14 pg/ml versus 3945.16±577.11 pg/ml, p = 0.351). Mean value of estriol study group who delivered preterm (3512.85±586.16 pg/ml) was higher as compared to the mean value of control group (2691.72±681.08 pg/ml) and difference was significant (p value < 0.001).

Conclusions: Thus, there is significant rise in level of saliva estriol, it can be used as a predictor for detecting symptomatic and asymptomatic women at risk for preterm birth.


Estriol, Preterm labour, Progesterone, Saliva

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Lumley J. Defining the problem the epidemiology of preterm birth. BJOG. 2003;110Suppl 20:3-7.

Creasy RK, Merkatz IR. Prevention of preterm birth: Clinical opinion. Obstet Gynecol. 1990;76(1 Suppl):2S-4S.

McGarrigle HHG, Lachelin GCL. Increasing saliva (free) estriol to progesterone ratio in late pregnancy: a role for estriol in intiating spontaneous onset of labour at term. BMJ. 1984;287:457-9.

Darne J, McGarrigle HHG, Lachelin GCL. Saliva estriol, estadiol, estrone and progesterone levels in pregnancy: spontaneous labour at term is preceded by arise in the saliva estrol progesterone ratio. BJOG. 1987;94:227-35.

Kundu N, Novak N, Petersen LP. Salivary unconjugated estriol levels in normal third trimester pregnancy–direct correlation with serum levels. Steroids. 1983;41:145-53.

Vining RF, McGinley R, Rice BV. Saliva estriol measurements: an alternative to the assay of serum unconjugated estriol in assessing feto-placental function. J Clin Endocrinol Metab. 1983b;56:454-60.

Luisi M, Franchi F, Kicovic PM, Silvestri D, Cossu G, Catarsi AL, et al. Radioimmunoassay for progesterone in human saliva during the menstrual cycle. J Steroid Biochem. 1981;14:1069-73.

Choe JK, Khan-Dawood FS, Dawood MY. Progesterone and estradiol in the saliva and plasma during the menstrual cycle. Am J Obstet Gynecol 1983;147:557-62.

Lachelin GCL, McGarrigle, Seed PL. Low saliva progesterone concentrations are associated with spontaneous every preterm labour (before 34 weeks of gestation) in women at increased risk of preterm delivery. Br J Obstet Gynaecol. 2009;116:1515-9.

Klebanoff MA, Meis PJ, Dombrowski MP, Zhao Y, Moawad AH, Northen A, et al. Salivary progesterone and estriol among pregnant women treated with 17-a- hydroxyprogesterone caproate or placebo. Am J Obstet Gynecol. 2008;199:506.e1-506.e7.

McGregor JA, Jackson GM, Lacheln GCL, Goodwin TM, Artal R, Hastings C, et al. Salivary estriol as risk assessment for preterm labour: a prospective trial. Am J Obstet Gynecol. 1995;173:1337-42.