Accuracy of a home-based device for giving an early estimate of pregnancy duration compared with reference methods.
OBJECTIVE
To assess a home pregnancy test's accuracy to concurrently detect pregnancy and determine pregnancy duration.


METHODS
Multicenter, prospective study.


METHODS
Study sites in the United States.


METHODS
Women actively attempting to conceive who have menstrual bleeds (18-45 years).


METHODS
Volunteers collected early morning urine samples (three or fewer menstrual cycles). Pregnant volunteers underwent ultrasound dating scans. Ovulation day (LH surge +1 day) during pregnancy-resulting cycles was determined by quantitative measurement of LH. Random urine samples were tested with the hCG-measuring pregnancy test from 4 days before the expected period until 4 weeks later.


METHODS
A home pregnancy test's accuracy in determining pregnancy duration compared with ultrasound and ovulation day.


RESULTS
Agreement between pregnancy test results and time since ovulation was 93% (confidence interval [CI], 91.5-94.4). Agreement with ultrasound was dependent on the formula: there was 99% agreement when calculated with adjustment for Hadlock formula bias (Pexsters; CI, 98.2-99.4) or using a nonbias formula (Wu; CI, 98.6-99.6), when ultrasound error was accommodated. Agreement was lower when bias/measurement errors were not accounted for (Wu, 86%, CI, 83.9-88; Hadlock, 80.8, CI, 78.2-83.3).


CONCLUSIONS
This home pregnancy test provides an accurate estimation of pregnancy duration in weeks categories, 1-2, 2-3, 3+ weeks since ovulation, thereby showing utility in dating pregnancy.
SPD Development Company Limited, Bedford, United Kingdom. Electronic address: sarah.johnson@spdspark.com.
Sarah R
SR
Johnson
Sonya
S
Godbert
Paul
P
Perry
Pauline
P
Parsons
Louise
L
Roberts
Philip
P
Buchanan
John
J
Larsen
Todd A
TA
Alonzo
Michael
M
Zinaman
D000293:Adolescent; D000328:Adult; D059026:Diagnostic Self Evaluation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D008875:Middle Aged; D010061:Ovulation Detection / Q000295:instrumentation* / Q000706:statistics & numerical data*; D011247:Pregnancy; D011258:Pregnancy Tests / Q000295:instrumentation* / Q000706:statistics & numerical data*; D011933:Reagent Kits, Diagnostic / Q000706:statistics & numerical data*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D061685:Time-to-Pregnancy; D014481:United States / Q000453:epidemiology; D055815:Young Adult
D011933:Reagent Kits, Diagnostic
Pregnancy duration; human chorionic gonadotropin (hCG); ultrasound