Last registered on November 01, 2023


Trial Information

General Information

Initial registration date
October 26, 2023

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
November 01, 2023, 3:56 PM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.


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Primary Investigator

Universidad de Montevideo

Other Primary Investigator(s)

PI Affiliation
Universidad de Montevideo
PI Affiliation
Universidad de Montevideo

Additional Trial Information

On going
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
We assess whether an intervention combining mobile technology and behavioral sciences that reaches out to pregnant women and their partners with timely information, nudges and support strategies, contributes to improve pregnancy, birth outcomes, and childrearing behaviors. Smartphones provide fast, comprehensive and sustainable access to women, and can be easily linked to institutional level data that can help personalize information. Research from behavioral economics suggests that information presented in the right way and at the right time can help reorient parental decisions towards children's fundamental development.

We give pregnant women and their partners access to a chatbot (via WhatsApp) where they can search for information on pregnancy, birth and positive parenting and where they receive messages that nudge them towards adopting healthy habits, managing emotional health, improving parental competencies, and relying on support networks. The intervention starts at gestation week 12 and ends 24 weeks after birth.

We evaluate the program using a randomized design (N=1500). We recruit participants from local primary care clinics, both public and private, and randomize them to receive the full treatment (full access to the chatbot and messages) or to receive partial treatment (access to infographs on fetal development by gestation week and to a chatbot with limited information (a listing of local resources and useful telephone numbers).

The program can allow policymakers to intervene much earlier, preemptively, and on a larger scale. We expect it to lead to improved and more equitable pregnancy, birth, and child development outcomes.
External Link(s)

Registration Citation

Experimental Details


The intervention consists of a series of e-messages and a chatbot menu, made available via WhatsApp, with information, resources and nudges that support and educate expecting parents throughout pregnancy and the first months after birth. The messages are sent to the pregnant woman and her partner (if any) four times a week from the moment the woman is recruited at gestation week 12 up to 6 months after birth. The messages are personalized with the name of the pregnant woman, her partner's, and the child's (after birth), and are adapted to the pregnancy's gestational age at recruitment (if after week 12), the pregnant woman’s marital status (alone or with a partner), the pregnant woman's emotional state, baseline information on support networks and enjoyable activities, and whether the child is delivered prematurely.

The content of the pregnancy chatbot menu and messages is based on three pillars: (i) promoting healthy habits (physical activity, healthy eating, avoiding psychoactive substances), (ii) maintaining a healthy mental and emotional state, and (iii) promoting support networks. The chatbot also includes information about available health care resources (health clinics, pregnancy workshops, sequence of normal check-ups, ecosounds and diagnostic tests) and useful telephone numbers and hotlines. The program is, in addition, used to screen mental health problems and refer women to treatment if needed. At baseline, women are screened for domestic violence, food insecurity, and mental health problems and derived to social workers or mental health specialists accordingly. Then, every two weeks, women receive a "mood-checker" message inquiring about her emotional status. If she indicates not feeling well for two consecutive mood-checking messages, the program activates a protocol in which the woman has to complete a depression screener and is eventually derived to a mental health specialist.

Once the child is born, a new menu is displayed in the chatbot and caregivers begin to receive a new set of messages and alerts, based on four parenting competencies: (i) affection and good treatment; (ii) protection, including routines and a safe environment; (iii) stimulation, including playing with the child, talking to the child, reading and telling stories; and (iv) parental self-care and reflection. This stage is implemented for 24 weeks after delivery.

The contents of the chatbot and messages are aligned with information and resources currently delivered to pregnant women, and caregivers through different programs at the national and international level (WHO, UNICEF, Ministry of Health, Ministry of Social Development).

The structure of the messages addresses behavioral biases that play against an optimal pregnancy and parenthood, including negative identities, status quo bias, present bias, and cognitive inattention.The first message is an infograph with information on child development at the woman's age of gestation. The second message provides information on the future benefits of certain behaviors or attitudes, the third message suggests specific tips or activities to implement during the week associated to that topic, and the last one encourages reflection or motivates the participant to complete the previous activity.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
(a) Maternal knowledge and behaviors during pregnancy:
(b) Maternal wellbeing
(c) Birth outcomes
(d) Parental caregiving behaviors
(e) Child development at 6 months
Primary Outcomes (explanation)
a) Maternal knowledge and behaviors during pregnancy: (i) increase maternal knowledge about pregnancy; (ii) increase physical activity; (iii) improve nutrition habits; (iv) more adequate weight gain; (v) reduce tobacco and/or alcohol use; (vi) increase attendance to childbirth preparation workshops.
b) Maternal wellbeing: (i) Reduce depression symptoms; (ii) improve well-being; (iii) increase early detection and referrals for women with depression/anxiety; (iv) more frequent activation of family and affective support networks.
c) Better neonatal outcomes: (i) reduce the fraction of pre-term births; (ii) increase gestation length; (iii) reduce the percentage of small-for-gestational-age (SGA) children; (iv) increase birthweight; (v) increase the fraction of children with adequate weight (above 2500 and below 4000 grams); (vi) reduce child's length of stay in the hospital; (vii) reduce mother's length of stay in the hospital; (viii) reduce rate of c-sections.
d) Improvements in parental childrearing behaviors and childrearing environment: (i) increase parental knowledge about positive parenting practices and attitudes; (ii) increase the frequency of parental involvement in positive parenting practices (breastfeeding, routines, timely vaccination, reading, play); (iii) improve the quality of interaction between child and caregiver (good treatment, affection, observation, response and sensitive interpretation); iv) increase father’s involvement.
e) Improvements in child development at 6 months: increase motor, cognitive, socio-emotional and language development.

Secondary Outcomes

Secondary Outcomes (end points)
We expect these effects to be stronger for women of lower socioeconomic status, for those expecting a first child, for those with higher health risks (older than 35, smoker prior to pregnancy, overweight or obese, with a history of diabetes or hypertension), for those with mental health problems or emotional distress, for those with negative identities (lower self-confidence about pregnancy and parenthood), for those experiencing more negative shocks (which proxy for inattention), and for those with less self-control (proxying present bias and status quo bias).
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The intervention will be evaluated using a randomized controlled trial.

Participants and exclusion criteria
Participants include pregnant women and their partners who control their pregnancies in public and private primary care clinics in Montevideo's metropolitan area (Metropolitan RAP).

Pregnant women below the age of 15 will be excluded.

Women will be recruited by primary care administrative staff during the coordination of the nuchal translucency ultrasound (before gestation week 12), both by phone or face-to-face.

Informed consent
A member of the implementation team will inform the pregnant women about the pilot program, the implications of her participation and her right to withdraw at any time. She will be asked whether she wants to involve her partner in the program and share her partner's mobile phone. Finally, she will be asked to sign an informed consent in which she accepts to share survey data and birth data for research purposes. The participant will sign the consent by typing her name in a form provided by the interviewer through WhatsApp.

Once a week, all pregnant women who have been contacted by the clinic coordinator for the NT ultrasound, satisfy the inclusion criteria, and have given their informed consent to participate will be randomized to treatment or to a comparison group. To reach the target number of participants, we expect to recruit women for a period of 10 months. The treatment group has full acces to the chatbot (with links to a large body of information on pregnancy and parenting topics) and to 4 messages per week. The comparison group has access to one message per week with information on fetal development by that week's gestation age and to a simplified chatbot with limited information on local resources and useful telephone numbers.

We randomize women within strata defined by the health care provider (4 providers) and by the woman's mental health status at baseline (risk of depression).
Experimental Design Details
Not available
Randomization Method
Randomization is done in an office by a computer once a week for 10 months, using a fixed seed.
Randomization Unit
Randomization will be at the individual (pregnant woman) level, within strata defined by the provider (4 providers) and a dummy reflecting risk of mental health problems.
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Sample size: planned number of observations
Sample size (or number of clusters) by treatment arms
N=750 treatment group
N=750 control group
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Power calculations: MDE for a sample of N=1500 1) PREGNANCY RESULTS Data: baseline survey (gestation age 12) a) Improve nutrition habits (index of positive nutrition habits, with max of 10) mean=6.125313 sd= 1.869979 N=1500 ; MDE=0.27 (0.145 sd) b) Reduce fraction of smokers at 3rd trimester % women that smoke in 3rd trimester=0.082 N=1500; MDE = -0.0355 (43%) c) Reduce depression symptoms (Edinburgh scale) Mean = 6.18797 Sd = 4.870407 N=1500 EMD = -0.7051 (0.145 sd) d) Reduce risk of depression (Edinmburgh scale > 10) Mean = 0.204 N=1500 EMD = -0.0551 (25%) 2) BIRH OUTCOMES Data: Perinatal Informatic System (admin) a) Increase weeks of gestation at birth Mean=38.4 weeks Sd= 2 weeks. N=1500 MDE = 0.145 standard deviations b) Increase birthweight Mean =3252 g Sd = 584 g MDE = 0.20 sd  N=788 (394 in each arm). N=1500  MDE = 0.145 sd c) Decrease prematurity p =0.099 N=1500; MDE = -0.0391 (39%) d) Increase births with birthweigth between 2500 gr and 4000 gr (reduce low birth weight and macrosomy) % births with weight<2500 & weight >4000 = 84.17% N=1500 ; MDE = 0.0492 (5.8%) e) Reduce child’s length of stay at the hospital Mean (days) = 3.4847 Sd = 6.1335 N=1500 ; MDE = -0.8879 (0.145 sd) f) Reduce mother’s length of stay at the hospital Mean (days) = 3.887928 sd = 8.347203 N=1500; MDE = -1.2084 (0.145 sd) g) Reduce C-sections Rate of c-section = 0.4977303 N=1500; MDE= 0.0721 (14.5%) 3) POST-BIRTH OUTCOMES a) Parental time investment index mean=12.971 sd=1.932 N=1500; MDE=-0.2791 (0.145 sd) b) Parental involvement in physical games mean=4.191 sd=0.785 N=1500; MDE=-0.2791 (0.145 sd) c) Parental involvement in didactic activities mean=4.825 sd=0.989 N=1500; MDE= 0.1432 (0.145 sd) d) Father's involvement in childrearing mean=0.769 sd=0.352 N=1500; MDE=0.0510 (0.145 sd) e) Parental sense of efficacy mean=0.4129 sd=0.806 N=1500; MDE=0.1167 (0.145 sd) f) Parental stress - dysfunctional interaction mean=20.619 sd=6.305 N=1500; MDE=-0.9127 (0.145 sd)
Supporting Documents and Materials

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Institutional Review Boards (IRBs)

IRB Name
Centro Hospitalario Pereira Rossell, Dirección General, Comité de Etica en Investigación
IRB Approval Date
IRB Approval Number