About Our Study

Condition studied: non-immune hydrops fetalis (NIHF)


Contact the study team: [email protected] or 1-800-RX-FETUS


What is hydrops?

Hydrops fetalis is a condition in pregnancy marked by abnormal collections of fluid in the developing fetus. There are two types of hydrops. One is immune in nature, and results from blood type incompatibility between the pregnant woman and fetus. The other type is non-immune hydrops fetalis (NIHF), which can be caused by many types of genetic abnormalities, infections, and other causes. The majority of hydrops cases today are NIHF, and this is the condition that we are studying.


NIHF carries significant risks of stillbirth during the pregnancy, as well as of early delivery and serious illness and death for the newborn. There is also risk to the pregnant woman of developing a condition called mirror syndrome, which can include high blood pressure, swelling, and damage to organs such as the kidneys and liver. These risks vary widely by the underlying cause of the NIHF.


Our research has shown that the cause of at least half of all NIHF cases remains unknown after standard-of-care testing that includes karyotype and microarray. Importantly, without an understanding of the reason for the NIHF, prenatal care for a pregnancy with NIHF is less focused, clear plans for newborn care cannot be made, and the chance of NIHF happening again in a future pregnancy cannot be accurately estimated.


Download the Non-Immune Hydrops Fetalis Workup for our recommended workup for NIHF.


Purpose and importance of this study

The HyDROPS study (Hydrops: Diagnosing and Redefining Outcomes with Precision Study) applies a broad genetic test, called trio exome sequencing, to discover genetic diseases underlying NIHF. The information resulting from this study will:

  • Allow medical providers to focus prenatal management according to the underlying cause.
  • Inform participants about what to expect after birth.
  • Enable medical providers and parents to make clear plans for the newborn, including treatments that are best given soon after birth.
  • Inform participants and medical providers about the chance of NIHF happening again in a future pregnancy.

Our goals are to develop a precision-based approach to the diagnosis and care for NIHF in order to optimize both newborn and maternal outcomes. Ultimately, our group aims to develop novel, specific in utero treatments for each underlying cause of NIHF.



Download HyDROPS Brochure for Participant
Download HyDROPS Brochure for Medical Provider


Sponsors:  Fetal Health and Brianna Marie Foundations, National Institutes of Health, UCSF


ClinicalTrials.gov Identifier  NCT03412760