Data analysis
All relevant trials are merged, checked and screened to exclude
unqualified items. Microsoft EXCEL was used for descriptive statistics
of the data, and then the trials were classified according to the
following specific therapeutic areas (rank by quantity):
anesthesia/analgesia; anti-infectiousagents (including treatment and
prevention); endocrine diseases (mainly gestational diabetes mellitus
(GDM) and thyroid diseases); postpartum hemorrhage (PPH) (only include
the trials where subjects took the investigational drugs before giving
birth); inducers; premature delivery/delivery; preeclampsia and
pregnancy-induced hypertension (PIH); miscarriage and recurrent
miscarriage; dietary supplement to improve pregnancy outcome; vomiting.
The total number of trials in each database was compared with the number
of trials relevant to pregnancy, and the comparison was expressed in
percentage and original number. Analysis by region includes the location
of the initiator and study sites. If the trial was conducted by
different sites in the same region, it falls in the cumulative
calculation for that region. Our analysis focused on three aspects of
pregnancy trials: the overall finding of initial trials conducted
between 2013 and 2020 (number, drug type, and study design); the
therapeutic areas; and the geographical distribution of all clinical
trial institutes and industry funds.