Why participate?

  • You will receive results from detailed genetic testing (trio exome sequencing) that are important for your pregnancy, your child, and/or future pregnancies.   
  • Your participation helps us to better understand NIHF and improve our care for patients with this condition.
  • Findings from this study will guide development of in utero treatments for specific genetic diseases that cause NIHF.

Who may enroll in our study?

Participants may enroll in this study during pregnancy or after pregnancy. We can enroll participants remotely over video or telephone; travel to UCSF is not necessary to participate in the study.


Inclusion criteria:

We are enrolling participants who are pregnant with a fetus diagnosed with NIHF, or infants who had a diagnosis of NIHF in utero, when standard genetic testing (karyotype or microarray) does not explain the NIHF. We accept a broad definition of NIHF, which includes one or more of the following:

  • One or more abnormal fluid collections in the fetus (such as fluid around the heart or in the lungs, abdomen, or skin)
  • Cystic hygroma
  • Increased nuchal translucency 3.5 mm

Exclusion criteria:

  • Pregnancy with immune hydrops
  • Twin pregnancy with evidence of twin-twin transfusion syndrome

What to expect if I enroll in the study?

For NIHF pregnancies that are not clearly explained by standard genetic testing (karyotype or microarray), we offer trio exome sequencing through our UCSF Genomic Medicine Laboratory at no cost to families participating in the study. With trio exome sequencing, we examine more than 20,000 genes in the DNA of the fetus or infant to determine whether there are genetic variations that explain the NIHF. Samples from each biological parent are also used to determine whether these genetic changes are inherited. This testing can also be done using a sample from only one parent if both are not available. UCSF has prepared a video to explain trio exome sequencing.


Participants will meet twice with study team by telephone or video (or potentially in person if the patient is already a UCSF patient).  During the first meeting, we will explain the study and genetic testing, and answer all questions about participation.  During the second meeting, we will return results of the trio exome sequencing and answer all quetions about the results.  We also provide a formal report of the results that participants can keep for their records.


For ongoing pregnancies and live infants, we expedite testing and return results in approximately 2-4 weeks. For non-continuing pregnancies, we return results in approximately 8-10 weeks. For each case, a multidisciplinary panel of experts at UCSF carefully reviews the testing results and determines the significance of genetic variations found.


What types of samples can be used for the exome sequencing?

Only one sample type is needed for the fetus or infant, as well as for each biological parent. Fetal and newborn samples can be obtained from procedures already performed, such as a prior amniocentesis.

  • Fetus: cultured amniocytes, extracted DNA, cord blood, or other types of samples
  • Newborn: blood, buccal (cheek) swab, or other types of samples
  • Parent: blood or saliva (NOTE: We can ship saliva kits to participants’ homes with pre-paid shipping labels for easy return to our lab at UCSF.)

How can I participate?

If you would like to participate in the study or want more information, please either email our study team at [email protected] or call 1-800-RX-FETUS.