Fitbit Activity Tracker to Predict Risk of Preterm Birth

Preterm birth (PTB) remains one of the leading causes of neonatal morbidity and mortality,
with a variety of modifiable and non-modifiable risk factors. In an attempt to prevent PTB,
activity restriction is one of the most commonly prescribed interventions in obstetrics, with
the idea that decreasing activity will mitigate the risk of a preterm delivery (PTD).
However, there has been a lack of evidence in the literature to support this theory. In fact,
multiple studies have demonstrated that decreased activity levels have decreased time to
delivery in both women with a short cervix, as well as nulliparous patients at increased risk
for PTB.

Approximately 40% of deliveries in the United States are nulliparous. For this overwhelming
large portion of women, a knowledge gap exists in assessing their risk for PTB. The most
powerful risk factor for PTB, a previous PTB, is not applicable to this cohort of women. The
precise etiology of PTB in nulliparous women remains unknown but factors found to be
associated have included health behaviors , as well as being part of disadvantaged
populations. Studies have demonstrated a significant racial disparity in PTB, contributing to
the disproportionally worse fetal outcomes in minority populations. Institutional racism,
reported stress levels and discrimination have all been identified as risk factors for PTB.

Interventions to prevent PTB have thus far found to be ineffective, and therein likes an
opportunity to identify risk factors in this largely unstudied population and create
measures, focusing on behavior modification and acknowledging related risks of health
disparities to impact maternal and neonatal outcomes.

Currently there are no published prospective studies using quantitative measures to evaluate
physical activity in relation to gestational age at delivery. Based on a cohort design, our
objective is to use a Fitbit activity tracking device, and assess nulliparous patients. Our
hypothesis is that higher physical activity measured in steps per day will be associated with
a later gestational age at delivery.

Each participant will be given a Fitbit, complementary of participating in the study. Women
will be instructed to wear the Fitbit to measure physical activity throughout the duration of
the entire pregnancy, 24 hours a day. The Fitbit has been shown to be valid measure of steps
under laboratory conditions. Also, the Fitbit provides estimates of "sedentary", "light",
"fairly active" and "very active" minutes as daily accumulated totals. All data from the
Fitbit device will be acquired using the Fitabase software system. Fitabase is a research
software platform that collects data from devices remotely in near real time as devices sync
and update to the Fitabase dashboard. It creates spreadsheet exports of reported data, which
can be retrieved remotely by investigators. Fitabase stores the data collected in high
security data centers, and only permitted research personnel can access the data.

Upon enrollment in the study, researchers will administer the Fitbit device to each study
participant. Researchers will register participants with the Fitabase software system, giving
them a unique anonymous patient identifier, which will link each patient and their Fitbit to
the Fitabase software system. User accounts will be created by the enrolling researcher for
each participant account authorizing access to the Fitbit data for study personnel only. The
data collected from the Fitbit is continuously uploaded remotely from the wearable device to
the Fitabase software; new information is uploaded every 20 minutes. The device only holds a
total of 7 days of patient activity information, so the participant will be required to sync
their device to the software system every 7 days. This is done by an app, which is downloaded
on the participants' phone at the enrollment of the study. Of note, Fitbit data (ie: steps,
activity monitoring) will be blinded to the participants; the Fitbit device has no visible
monitoring screen. Research assistants will monitor compliance of participants to syncing
their Fitbit and will be sent an email reminder if they do not sync the Fitbit within the
last five days. Days with '0' minutes of registered activity will be considered non-valid and
set to missing.

Inclusion Criteria:

1. Documented single viable intrauterine pregnancy at the time of enrollment

2. Nulliparous women

3. At least 18 years of age

4. Access to a smart phone or computer

Exclusion Criteria:

- Known or suspected major congenital anomalies or aneuploidy

- Fetal demise

- Multiple gestation

- Known maternal medical complications (increasing patient risk for indicated (planned)
preterm delivery:

- Pre-gestational diabetes White's Class D or worse

- Cancer (undergoing treatment)

- Current hyperthyroidism if not adequately controlled

- Renal disease with altered renal function (serum creatinine > 1.5)

- Systemic lupus, scleroderma, polymyalgia rheumatica

- Active liver disease (acute hepatitis, chronic active hepatitis, persistently
abnormal liver enzymes)

- Platelet or red blood cell disorder

- Chronic pulmonary disease (aside from asthma)

- Structural, functional or ischemic heart disease. Neither mitral valve prolapse
nor paroxysmal supraventricular tachycardia are considered exclusions.

- Known HIV positive with viral load greater than 1,000 copies/ml or CD4 count less
than 350/mm3

- Current or planned cerclage

- Planned delivery prior to 37 weeks

- Planned delivery at a non-participating hospital

- Patients who do not have regular access to a smart phone or computer